feat(validations): merchant (bar/lavazh) ticket validations end-to-end

In-park merchants discharge customers' parking: a merchant user scans the
ticket on their device (/validate; validation:create + program↔user binding)
and applies their program — comp / first-N-minutes free / amount-off (capped,
typed at scan) / percent. All money stays at the booth: the quote folds live
validations in a canonical order (timeCredit → percent → fixed → comp, net
floors at 0, Σ lines ≡ gross − net), the payment records gross/discount and
CONSUMES the validation ids (an overstay's fresh period never re-applies
them), the receipt prints the gross → lines → net story, and the Z/X-report
carries discountTotalMinor leakage. Every apply/void is a signed, attributed
ledger event (refId = append-only void); program config is /setup/site master
data (Bar/Lavazh checkboxes + right-column panel, tabs when both) whose saves
sign config_change. Migration 0024 + reset-db drift-guard entries; 8 route
integration tests + priceSession fold suite.

See wiki/concepts/validation-discounts.md for the full design record.

Claude-Session: https://claude.ai/code/session_01YYkpEsLmoQPaize5ec3oUm

apps/web/src/BoothPayModal.tsx

@@ -383,6 +383,30 @@ export function BoothPayModal({ identity, onClose }: { identity: string; onClose
                   />
                 </div>
 
+                {/* Merchant validations (bar/lavazh): the gross fee + one line per
+                    discount — the Total below is the NET the customer pays. The lines
+                    ride the quote (SessionLookup.validationLines) and reprint on the
+                    receipt. See wiki/concepts/validation-discounts.md. */}
+                {!isSubscription &&
+                  (s.validationLines ?? []).length > 0 &&
+                  s.currency != null &&
+                  s.amountMinor != null && (
+                    <div className="rounded-term bg-term-panel-2 px-3 py-2 text-[0.75rem]">
+                      <div className="flex justify-between text-term-text">
+                        <span>{t("val.gross")}</span>
+                        <span className="tabular-nums">
+                          {formatMoney(s.grossMinor ?? s.amountMinor, s.currency)}
+                        </span>
+                      </div>
+                      {(s.validationLines ?? []).map((v, i) => (
+                        <div key={i} className="flex justify-between text-term-green">
+                          <span>{v.label}</span>
+                          <span className="tabular-nums">−{formatMoney(v.discountMinor, s.currency!)}</span>
+                        </div>
+                      ))}
+                    </div>
+                  )}
+
                 {/* Total — a subscription is prepaid (no amount) UNLESS it owes an
                     out-of-window window charge; then show that amount. For an overstay the
                     amount is the TOP-UP delta, not the whole stay. */}

apps/web/src/SiteSettings.tsx

@@ -1,6 +1,16 @@
 import { useEffect, useState } from "react";
 import { useTranslation } from "react-i18next";
-import { fetchOccupancy, fetchSiteConfig, saveSiteConfig, type Occupancy, type SiteConfig } from "./api.js";
+import {
+  fetchOccupancy,
+  fetchSiteConfig,
+  fetchValidationPrograms,
+  saveSiteConfig,
+  saveValidationProgram,
+  type Occupancy,
+  type SiteConfig,
+  type ValidationProgramView,
+} from "./api.js";
+import { STATIONS, ValidationStationsPanel, defaultProgram, type StationId } from "./ValidationSetup.js";
 
 // Live occupancy + capacity + park metadata. Occupancy is shown to everyone (it's a
 // fold over the signed ledger); capacity and the metadata fields are admin-editable.
@@ -28,12 +38,21 @@ export function SiteSettings({ canEdit }: { canEdit: boolean }) {
   const [reserveSubs, setReserveSubs] = useState(false);
   const [anprEntry, setAnprEntry] = useState(true);
   const [msg, setMsg] = useState<string | null>(null);
+  // Merchant-validation programs (bar / lavazh). The checkboxes below toggle a
+  // station's `active` (persisted at once — each flip signs a config_change); the
+  // right-column panel edits the enabled stations. See validation-discounts.md.
+  const [programs, setPrograms] = useState<ValidationProgramView[]>([]);
 
   function reload() {
     fetchOccupancy().then(setOcc).catch(() => {});
   }
   useEffect(() => {
     reload();
+    if (canEdit) {
+      fetchValidationPrograms()
+        .then((r) => setPrograms(r.programs))
+        .catch(() => {});
+    }
     fetchSiteConfig()
       .then((c) => {
         setCapInput(c.capacity == null ? "" : String(c.capacity));
@@ -45,7 +64,23 @@ export function SiteSettings({ canEdit }: { canEdit: boolean }) {
         setMeta(m);
       })
       .catch(() => {});
-  }, []);
+  }, [canEdit]);
+
+  /** Flip a merchant station's checkbox: persist `active` at once (a signed
+   *  config_change server-side), creating the well-known row with comp defaults on
+   *  the first enable. Config details are edited in the right-column panel. */
+  async function toggleStation(id: StationId, active: boolean) {
+    const existing = programs.find((p) => p.id === id);
+    const body = existing
+      ? { ...existing, active }
+      : { ...defaultProgram(id, t(id === "bar" ? "val.enableBar" : "val.enableLavazh")), active };
+    try {
+      const saved = await saveValidationProgram(id, body);
+      setPrograms((ps) => [...ps.filter((p) => p.id !== id), saved]);
+    } catch (e) {
+      setMsg((e as Error).message);
+    }
+  }
 
   async function save() {
     setMsg(null);
@@ -68,7 +103,8 @@ export function SiteSettings({ canEdit }: { canEdit: boolean }) {
   }
 
   return (
-    <section className="card mt-6 max-w-md p-4">
+    <div className="mt-6 flex flex-wrap items-start gap-6">
+    <section className="card w-full max-w-md p-4">
       <div className="flex flex-wrap items-center gap-1.5 text-[0.8125rem]">
         <strong className="uppercase tracking-wider text-term-muted">{t("site.occupancy")}</strong>
         {occ == null ? (
@@ -127,6 +163,23 @@ export function SiteSettings({ canEdit }: { canEdit: boolean }) {
               <span className="hint block">{t("site.anprEntryHint")}</span>
             </span>
           </label>
+          <div className="border-t border-term-border pt-3 text-[0.6875rem] uppercase tracking-wider text-term-muted">
+            {t("val.sectionTitle")}
+          </div>
+          <span className="hint -mt-2">{t("val.sectionHint")}</span>
+          <div className="flex gap-6">
+            {STATIONS.map((id) => (
+              <label key={id} className="flex items-center gap-2 text-[0.75rem] text-term-text">
+                <input
+                  type="checkbox"
+                  className="accent-term-amber"
+                  checked={programs.find((p) => p.id === id)?.active ?? false}
+                  onChange={(e) => toggleStation(id, e.target.checked)}
+                />
+                {t(id === "bar" ? "val.enableBar" : "val.enableLavazh")}
+              </label>
+            ))}
+          </div>
           <div className="border-t border-term-border pt-3 text-[0.6875rem] uppercase tracking-wider text-term-muted">
             {t("site.parkDetails")}
           </div>
@@ -158,5 +211,12 @@ export function SiteSettings({ canEdit }: { canEdit: boolean }) {
         </div>
       )}
     </section>
+    {canEdit && (
+      <ValidationStationsPanel
+        programs={programs}
+        onSaved={(p) => setPrograms((ps) => [...ps.filter((x) => x.id !== p.id), p])}
+      />
+    )}
+    </div>
   );
 }

apps/web/src/ValidateScreen.tsx

@@ -0,0 +1,252 @@
+import { useEffect, useRef, useState } from "react";
+import { useTranslation } from "react-i18next";
+import {
+  applyValidation,
+  fetchMyValidationPrograms,
+  fetchValidationSession,
+  voidValidation,
+  type SessionUser,
+  type ValidationProgramView,
+  type ValidationSessionView,
+} from "./api.js";
+import { formatDuration, formatMoney, formatRelativeDateTime } from "./lib/format.js";
+
+// The MERCHANT screen (/validate): the bar/lavazh user's ENTIRE surface. Scan or key
+// the customer's ticket → see the session (deliberately NO money data — the booth
+// settles) → apply the bound program → done. Mobile-friendly: a phone/tablet on the
+// site LAN, or a booth-style USB HID scanner (it types digits + Enter into the
+// focused input). A mistake can be voided while UNUSED (append-only, signed).
+// Gated by validation:create + the server-side program↔user binding.
+// See wiki/concepts/validation-discounts.md.
+
+type Program = Omit<ValidationProgramView, "userIds">;
+
+/** Human line for what a program grants (the params live on the program row). */
+function programSummary(p: Program, t: (k: string, o?: Record<string, unknown>) => string): string {
+  if (p.mode === "comp") return t("val.modeComp");
+  if (p.mode === "timeCredit") return `${t("val.modeTimeCredit")}: ${p.minutes ?? 0} min`;
+  if (p.mode === "percent") return `${t("val.modePercent")}: ${p.percent ?? 0}%`;
+  return t("val.modeFixed");
+}
+
+export function ValidateScreen({ user }: { user: SessionUser }) {
+  const { t } = useTranslation();
+  const [programs, setPrograms] = useState<Program[] | null>(null);
+  const [programId, setProgramId] = useState<string | null>(null);
+  const [ticket, setTicket] = useState("");
+  const [view, setView] = useState<ValidationSessionView | null>(null);
+  const [amount, setAmount] = useState("");
+  const [msg, setMsg] = useState<{ kind: "ok" | "err"; text: string } | null>(null);
+  const [busy, setBusy] = useState(false);
+  const inputRef = useRef<HTMLInputElement>(null);
+
+  useEffect(() => {
+    fetchMyValidationPrograms()
+      .then((r) => {
+        setPrograms(r.programs);
+        if (r.programs.length === 1) setProgramId(r.programs[0]!.id);
+      })
+      .catch(() => setPrograms([]));
+    inputRef.current?.focus();
+  }, []);
+
+  const program = programs?.find((p) => p.id === programId) ?? null;
+
+  async function lookup(id?: string) {
+    const identity = (id ?? ticket).trim();
+    if (!identity) return;
+    setMsg(null);
+    try {
+      setView(await fetchValidationSession(identity));
+    } catch (e) {
+      setMsg({ kind: "err", text: (e as Error).message });
+    }
+  }
+
+  async function apply() {
+    if (!view || !program) return;
+    setBusy(true);
+    setMsg(null);
+    try {
+      const body: { identity: string; programId: string; amountMinor?: number } = {
+        identity: view.identity,
+        programId: program.id,
+      };
+      if (program.mode === "fixed") {
+        const n = Number(amount);
+        body.amountMinor = Number.isFinite(n) ? Math.round(n * 100) : 0;
+      }
+      await applyValidation(body);
+      setMsg({ kind: "ok", text: t("val.applied") });
+      setAmount("");
+      await lookup(view.identity);
+    } catch (e) {
+      setMsg({ kind: "err", text: (e as Error).message });
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  async function voidOne(eventId: string) {
+    if (!view) return;
+    if (!window.confirm(t("val.confirmVoid"))) return;
+    setMsg(null);
+    try {
+      await voidValidation({ eventId, identity: view.identity });
+      await lookup(view.identity);
+    } catch (e) {
+      setMsg({ kind: "err", text: (e as Error).message });
+    }
+  }
+
+  // The session's blocking condition, if any (not found / closed / subscriber).
+  const blocked =
+    view == null
+      ? null
+      : !view.found
+        ? t("val.notFound")
+        : view.subscription
+          ? t("val.subscription")
+          : !view.open
+            ? t("val.closed")
+            : null;
+
+  const alreadyApplied =
+    view != null &&
+    program != null &&
+    view.validations.some((v) => v.programId === program.id && !v.voided && v.consumedBy == null);
+
+  const fixedAmountOk =
+    program?.mode !== "fixed" ||
+    (Number(amount) > 0 &&
+      (program.maxAmountMinor == null || Math.round(Number(amount) * 100) <= program.maxAmountMinor));
+
+  return (
+    <div className="mx-auto mt-6 w-full max-w-md">
+      <section className="card p-4">
+        <div className="text-[0.6875rem] uppercase tracking-wider text-term-muted">{t("val.title")}</div>
+
+        {programs != null && programs.length === 0 && (
+          <p className="mt-3 text-[0.8125rem] text-term-red">{t("val.noPrograms")}</p>
+        )}
+
+        {programs != null && programs.length > 1 && (
+          <div className="mt-3 flex gap-1">
+            {programs.map((p) => (
+              <button
+                key={p.id}
+                type="button"
+                className={`btn btn-sm ${p.id === programId ? "btn-primary" : "btn-ghost"}`}
+                onClick={() => setProgramId(p.id)}
+              >
+                {p.name}
+              </button>
+            ))}
+          </div>
+        )}
+        {program && <p className="mt-1 text-[0.75rem] text-term-muted">{program.name} — {programSummary(program, t)}</p>}
+
+        <form
+          className="mt-3 flex gap-2"
+          onSubmit={(e) => {
+            e.preventDefault();
+            void lookup();
+          }}
+        >
+          <input
+            ref={inputRef}
+            className="input flex-1 tabular-nums"
+            inputMode="numeric"
+            value={ticket}
+            onChange={(e) => setTicket(e.target.value)}
+            placeholder={t("val.scanPrompt")}
+          />
+          <button type="submit" className="btn btn-primary btn-sm">{t("val.lookup")}</button>
+        </form>
+
+        {msg && (
+          <p className={`mt-2 text-[0.8125rem] ${msg.kind === "ok" ? "text-term-green" : "text-term-red"}`}>
+            {msg.text}
+          </p>
+        )}
+
+        {view && (
+          <div className="mt-3 border-t border-term-border pt-3">
+            {blocked ? (
+              <p className="text-[0.8125rem] text-term-red">{blocked}</p>
+            ) : (
+              <>
+                <div className="flex items-baseline justify-between text-[0.8125rem]">
+                  <span className="font-semibold tabular-nums text-term-text">{view.identity}</span>
+                  <span className="text-term-muted">
+                    {t("val.entry")} {formatRelativeDateTime(view.enteredAt, t)}
+                    {view.enteredAt && <> · {formatDuration(view.enteredAt, new Date().toISOString())}</>}
+                  </span>
+                </div>
+
+                {program && !alreadyApplied && (
+                  <div className="mt-3 grid gap-2">
+                    {program.mode === "fixed" && (
+                      <div className="field">
+                        <span className="label">
+                          {t("val.amountLabel")}
+                          {program.maxAmountMinor != null && (
+                            <span className="hint ml-2">
+                              {t("val.amountHint", { max: formatMoney(program.maxAmountMinor, "") })}
+                            </span>
+                          )}
+                        </span>
+                        <input
+                          className="input w-40 tabular-nums"
+                          inputMode="decimal"
+                          value={amount}
+                          onChange={(e) => setAmount(e.target.value)}
+                          placeholder="300"
+                        />
+                      </div>
+                    )}
+                    <button
+                      type="button"
+                      className="btn btn-primary"
+                      disabled={busy || !fixedAmountOk}
+                      onClick={apply}
+                    >
+                      {t("val.apply")}
+                    </button>
+                  </div>
+                )}
+
+                {view.validations.length > 0 && (
+                  <div className="mt-3">
+                    <div className="label">{t("val.existing")}</div>
+                    <ul className="mt-1 grid gap-1">
+                      {view.validations.map((v) => (
+                        <li key={v.eventId} className="flex items-center gap-2 text-[0.75rem] text-term-text">
+                          <span>{v.label}</span>
+                          {v.amountMinor != null && <span className="tabular-nums">−{formatMoney(v.amountMinor, "")}</span>}
+                          {v.minutes != null && <span>{v.minutes} min</span>}
+                          {v.percent != null && <span>{v.percent}%</span>}
+                          {v.voided ? (
+                            <span className="text-term-muted">({t("val.voided")})</span>
+                          ) : v.consumedBy != null ? (
+                            <span className="text-term-muted">({t("val.used")})</span>
+                          ) : (
+                            v.operator === user.username && (
+                              <button type="button" className="btn btn-ghost btn-sm ml-auto" onClick={() => voidOne(v.eventId)}>
+                                {t("val.void")}
+                              </button>
+                            )
+                          )}
+                        </li>
+                      ))}
+                    </ul>
+                  </div>
+                )}
+              </>
+            )}
+          </div>
+        )}
+      </section>
+    </div>
+  );
+}

apps/web/src/ValidationSetup.tsx

@@ -0,0 +1,231 @@
+import { useEffect, useMemo, useState } from "react";
+import { useTranslation } from "react-i18next";
+import {
+  fetchUsers,
+  saveValidationProgram,
+  type ManagedUser,
+  type ValidationMode,
+  type ValidationProgramView,
+} from "./api.js";
+
+// The /setup/site RIGHT panel: per-station merchant-validation config (Bar / Lavazh).
+// The checkboxes on the left card toggle a station's `active`; this panel edits the
+// enabled stations' programs — one panel, tabs when both are on. Storage is generic
+// (validation_programs rows keyed "bar"/"lavazh"); the UI is deliberately these two
+// fixed stations. Amounts are entered in MAJOR units and stored in integer minor
+// units (the tariff-composer convention). See wiki/concepts/validation-discounts.md.
+
+/** The two well-known stations the checkboxes toggle. */
+export const STATIONS = ["bar", "lavazh"] as const;
+export type StationId = (typeof STATIONS)[number];
+
+/** A blank program draft for a station enabled for the first time. */
+export function defaultProgram(id: StationId, label: string): Omit<ValidationProgramView, "id"> {
+  return {
+    name: label,
+    mode: "comp",
+    minutes: null,
+    percent: null,
+    maxAmountMinor: null,
+    maxPerDay: null,
+    active: true,
+    userIds: [],
+  };
+}
+
+const toMinor = (s: string): number | null => {
+  const v = s.trim();
+  if (v === "") return null;
+  const n = Number(v);
+  return Number.isFinite(n) && n > 0 ? Math.round(n * 100) : null;
+};
+const fromMinor = (m: number | null): string => (m == null ? "" : String(m / 100));
+const toInt = (s: string): number | null => {
+  const v = s.trim();
+  if (v === "") return null;
+  const n = Number(v);
+  return Number.isInteger(n) && n > 0 ? n : null;
+};
+
+function StationForm({
+  program,
+  onSaved,
+}: {
+  program: ValidationProgramView;
+  onSaved: (p: ValidationProgramView) => void;
+}) {
+  const { t } = useTranslation();
+  const [name, setName] = useState(program.name);
+  const [mode, setMode] = useState<ValidationMode>(program.mode);
+  const [minutes, setMinutes] = useState(program.minutes == null ? "" : String(program.minutes));
+  const [percent, setPercent] = useState(program.percent == null ? "" : String(program.percent));
+  const [maxAmount, setMaxAmount] = useState(fromMinor(program.maxAmountMinor));
+  const [maxPerDay, setMaxPerDay] = useState(program.maxPerDay == null ? "" : String(program.maxPerDay));
+  const [userIds, setUserIds] = useState<Set<string>>(new Set(program.userIds));
+  const [users, setUsers] = useState<ManagedUser[] | null>(null);
+  const [msg, setMsg] = useState<string | null>(null);
+
+  // Reset the form when the tab switches to another station.
+  useEffect(() => {
+    setName(program.name);
+    setMode(program.mode);
+    setMinutes(program.minutes == null ? "" : String(program.minutes));
+    setPercent(program.percent == null ? "" : String(program.percent));
+    setMaxAmount(fromMinor(program.maxAmountMinor));
+    setMaxPerDay(program.maxPerDay == null ? "" : String(program.maxPerDay));
+    setUserIds(new Set(program.userIds));
+    setMsg(null);
+  }, [program.id]); // eslint-disable-line react-hooks/exhaustive-deps
+
+  useEffect(() => {
+    fetchUsers()
+      .then((r) => setUsers(r.users))
+      .catch(() => setUsers([]));
+  }, []);
+
+  const valid = useMemo(() => {
+    if (!name.trim()) return false;
+    if (mode === "timeCredit") return toInt(minutes) != null;
+    if (mode === "percent") {
+      const p = toInt(percent);
+      return p != null && p <= 100;
+    }
+    if (mode === "fixed") return toMinor(maxAmount) != null;
+    return true;
+  }, [name, mode, minutes, percent, maxAmount]);
+
+  async function save() {
+    setMsg(null);
+    try {
+      const saved = await saveValidationProgram(program.id, {
+        name: name.trim(),
+        mode,
+        minutes: mode === "timeCredit" ? toInt(minutes) : null,
+        percent: mode === "percent" ? toInt(percent) : null,
+        maxAmountMinor: mode === "fixed" ? toMinor(maxAmount) : null,
+        maxPerDay: toInt(maxPerDay),
+        active: program.active,
+        userIds: [...userIds],
+      });
+      onSaved(saved);
+      setMsg(t("val.saved"));
+    } catch (e) {
+      setMsg((e as Error).message);
+    }
+  }
+
+  const toggleUser = (id: string) =>
+    setUserIds((prev) => {
+      const next = new Set(prev);
+      next.has(id) ? next.delete(id) : next.add(id);
+      return next;
+    });
+
+  return (
+    <div className="mt-3 grid gap-3">
+      <div className="field">
+        <span className="label">{t("val.labelName")}</span>
+        <input className="input" value={name} onChange={(e) => setName(e.target.value)} placeholder={t("val.labelNamePh")} />
+      </div>
+      <div className="field">
+        <span className="label">{t("val.mode")}</span>
+        <select className="input w-fit" value={mode} onChange={(e) => setMode(e.target.value as ValidationMode)}>
+          <option value="comp">{t("val.modeComp")}</option>
+          <option value="timeCredit">{t("val.modeTimeCredit")}</option>
+          <option value="fixed">{t("val.modeFixed")}</option>
+          <option value="percent">{t("val.modePercent")}</option>
+        </select>
+      </div>
+      {mode === "timeCredit" && (
+        <div className="field">
+          <span className="label">{t("val.minutes")}</span>
+          <input className="input w-32" value={minutes} onChange={(e) => setMinutes(e.target.value)} placeholder="60" />
+        </div>
+      )}
+      {mode === "percent" && (
+        <div className="field">
+          <span className="label">{t("val.percent")}</span>
+          <input className="input w-32" value={percent} onChange={(e) => setPercent(e.target.value)} placeholder="100" />
+        </div>
+      )}
+      {mode === "fixed" && (
+        <div className="field">
+          <span className="label">{t("val.maxAmount")}</span>
+          <input className="input w-32" value={maxAmount} onChange={(e) => setMaxAmount(e.target.value)} placeholder="1000" />
+        </div>
+      )}
+      <div className="field">
+        <span className="label">{t("val.maxPerDay")}</span>
+        <input className="input w-32" value={maxPerDay} onChange={(e) => setMaxPerDay(e.target.value)} />
+      </div>
+      <div>
+        <div className="label">{t("val.users")}</div>
+        <span className="hint block">{t("val.usersHint")}</span>
+        <div className="mt-1 grid gap-1">
+          {users == null ? (
+            <span className="text-term-muted">…</span>
+          ) : users.length === 0 ? (
+            <span className="text-[0.75rem] text-term-muted">{t("val.noUsers")}</span>
+          ) : (
+            users.map((u) => (
+              <label key={u.id} className="flex items-center gap-2 text-[0.75rem] text-term-text">
+                <input
+                  type="checkbox"
+                  className="accent-term-amber"
+                  checked={userIds.has(u.id)}
+                  onChange={() => toggleUser(u.id)}
+                />
+                {u.username}
+                {u.fullName && <span className="text-term-muted">({u.fullName})</span>}
+              </label>
+            ))
+          )}
+        </div>
+      </div>
+      <div className="flex items-center gap-3">
+        <button type="button" className="btn btn-primary btn-sm" disabled={!valid} onClick={save}>
+          {t("site.save")}
+        </button>
+        {msg && <span className="text-[0.75rem] text-term-muted">{msg}</span>}
+      </div>
+    </div>
+  );
+}
+
+/** The right-column panel: tabs across the ENABLED stations, one form each. */
+export function ValidationStationsPanel({
+  programs,
+  onSaved,
+}: {
+  programs: ValidationProgramView[];
+  onSaved: (p: ValidationProgramView) => void;
+}) {
+  const { t } = useTranslation();
+  const enabled = STATIONS.map((id) => programs.find((p) => p.id === id)).filter(
+    (p): p is ValidationProgramView => p != null && p.active,
+  );
+  const [tab, setTab] = useState<string | null>(null);
+  const current = enabled.find((p) => p.id === tab) ?? enabled[0];
+  if (!current) return null;
+
+  return (
+    <section className="card w-full max-w-md p-4">
+      <div className="text-[0.6875rem] uppercase tracking-wider text-term-muted">{t("val.sectionTitle")}</div>
+      {enabled.length > 1 && (
+        <div className="mt-2 flex gap-1">
+          {enabled.map((p) => (
+            <button
+              key={p.id}
+              type="button"
+              className={`btn btn-sm ${p.id === current.id ? "btn-primary" : "btn-ghost"}`}
+              onClick={() => setTab(p.id)}
+            >
+              {t(p.id === "bar" ? "val.enableBar" : "val.enableLavazh")}
+            </button>
+          ))}
+        </div>
+      )}
+      <StationForm program={current} onSaved={onSaved} />
+    </section>
+  );
+}

apps/web/src/api.ts

@@ -7,7 +7,7 @@
 
 import { logFailedRequest } from "./lib/logger.js";
 import { apiUrl } from "./lib/origin.js";
-import type { AppLogRecord } from "@parking/shared";
+import type { AppLogRecord, ValidationLine, ValidationMode } from "@parking/shared";
 
 const CSRF_COOKIE = "parking_csrf";
 const CSRF_HEADER = "X-CSRF-Token";
@@ -1301,6 +1301,11 @@ export interface SessionLookup {
   subscriptionHolder: string | null;
   /** Advisory licence plate recognized for this session (ANPR). Null when none. */
   plate: string | null;
+  /** Merchant validations folded into `amountMinor` (which is NET): pre-discount fee,
+   *  total taken off, and the per-validation lines. See validation-discounts.md. */
+  grossMinor: number | null;
+  discountMinor: number | null;
+  validationLines: ValidationLine[];
 }
 
 /** Look up a ticket/session for the booth modal (entry/exit, paid, amount owed). */
@@ -1475,3 +1480,88 @@ export function updatePresenceBypass(patch: { radar?: boolean; camera?: boolean
 export function setCapacity(capacity: number | null): Promise<SiteConfig> {
   return saveSiteConfig({ capacity });
 }
+
+// --- Merchant validations (bar / lavazh) -----------------------------------
+// The merchant is VALIDATION-ONLY: they scan the ticket on their device and apply
+// their program; the booth settles NET of the applied validations and prints the
+// detailed receipt. Program config lives on /setup/site. See validation-discounts.md.
+
+export type { ValidationLine, ValidationMode } from "@parking/shared";
+
+/** An admin-composed program (mirrors the server row + its bound users). */
+export interface ValidationProgramView {
+  id: string;
+  name: string;
+  mode: ValidationMode;
+  minutes: number | null;
+  percent: number | null;
+  maxAmountMinor: number | null;
+  maxPerDay: number | null;
+  active: boolean;
+  userIds: string[];
+}
+
+/** A validation applied to a session, with its lifecycle state. */
+export interface AppliedValidationView {
+  eventId: string;
+  occurredAt: string;
+  programId: string;
+  label: string;
+  mode: ValidationMode;
+  minutes?: number;
+  amountMinor?: number;
+  percent?: number;
+  operator: string | null;
+  voided: boolean;
+  consumedBy: string | null;
+}
+
+/** The merchant screen's minimal session view — deliberately no money data. */
+export interface ValidationSessionView {
+  identity: string;
+  found: boolean;
+  open: boolean;
+  enteredAt: string | null;
+  subscription: boolean;
+  validations: AppliedValidationView[];
+}
+
+/** All programs + bound users (the /setup/site panel). site:read. */
+export function fetchValidationPrograms(): Promise<{ programs: ValidationProgramView[] }> {
+  return apiFetch("/api/validation/programs");
+}
+
+/** Upsert a program's config + binding set (site:update; signs a config_change). */
+export function saveValidationProgram(
+  id: string,
+  body: Omit<ValidationProgramView, "id">,
+): Promise<ValidationProgramView> {
+  return apiFetch(`/api/validation/programs/${encodeURIComponent(id)}`, {
+    method: "PUT",
+    body: JSON.stringify(body),
+  });
+}
+
+/** MY bound, active programs (the merchant screen). validation:create. */
+export function fetchMyValidationPrograms(): Promise<{ programs: Omit<ValidationProgramView, "userIds">[] }> {
+  return apiFetch("/api/validation/mine");
+}
+
+/** Merchant lookup of a scanned ticket (no money data). validation:create. */
+export function fetchValidationSession(identity: string): Promise<ValidationSessionView> {
+  return apiFetch(`/api/validation/session/${encodeURIComponent(identity)}`);
+}
+
+/** Apply my program to a ticket (signed, attributed). `amountMinor` only for fixed mode. */
+export function applyValidation(body: {
+  identity: string;
+  programId: string;
+  amountMinor?: number;
+}): Promise<{ ok: true; eventId: string; label: string }> {
+  return apiFetch("/api/validation/apply", { method: "POST", body: JSON.stringify(body) });
+}
+
+/** Void my own UNUSED validation (append-only correction). */
+export function voidValidation(body: { eventId: string; identity: string }): Promise<{ ok: true }> {
+  return apiFetch("/api/validation/void", { method: "POST", body: JSON.stringify(body) });
+}

apps/web/src/lib/i18n/en.ts

@@ -65,6 +65,7 @@ export const en: Catalog = {
     logs: "Logs",
     backup: "Backup",
     profile: "Profile",
+    validate: "Validations",
   },
   drawer: {
     stateTitle: "Drawer now",
@@ -230,6 +231,7 @@ export const en: Catalog = {
     evtCashOut: "PAY-OUT",
     evtCashReview: "REVIEW",
     evtConfigChange: "CONFIG",
+    evtValidation: "VALIDATION",
     decision: { authorize: "authorized", deny: "denied" },
     evtAnomaly: "ANOMALY",
     evtRefused: "REFUSED",
@@ -735,6 +737,51 @@ export const en: Catalog = {
     fieldPhone: "Phone",
     fieldEmail: "Email",
   },
+  // Merchant validations (bar / lavazh) — the /setup/site panel, the merchant's
+  // /validate screen, and the booth-modal discount lines. See validation-discounts.md.
+  val: {
+    // /setup/site
+    sectionTitle: "Merchant validations",
+    sectionHint: "An in-park merchant (bar / car-wash) scans the customer's ticket and grants a parking discount — payment and the receipt always stay at the booth.",
+    enableBar: "Bar",
+    enableLavazh: "Car wash",
+    labelName: "Receipt label",
+    labelNamePh: "e.g. Car wash — first hour free",
+    mode: "Discount type",
+    modeComp: "Parking fully free",
+    modeTimeCredit: "First minutes free",
+    modeFixed: "Amount off (typed at scan)",
+    modePercent: "Percent off",
+    minutes: "Free minutes",
+    percent: "Percent (%)",
+    maxAmount: "Cap per validation",
+    maxPerDay: "Max validations per day (blank = unlimited)",
+    users: "Validating users",
+    usersHint: "Only the selected users (whose role grants validation:create) can apply this program from their device.",
+    noUsers: "No users in the system — create one under Users.",
+    saved: "Saved.",
+    // /validate (the merchant screen)
+    title: "Ticket validation",
+    scanPrompt: "Scan or type the ticket number",
+    lookup: "Look up",
+    entry: "Entry:",
+    notFound: "No ticket found with this number.",
+    closed: "The ticket is closed (exited or voided).",
+    subscription: "This is a subscriber entry — not validatable.",
+    amountLabel: "Discount amount",
+    amountHint: "max {{max}}",
+    apply: "Apply validation",
+    applied: "Validation applied.",
+    existing: "Validations on this ticket",
+    voided: "voided",
+    used: "used in a payment",
+    void: "Void",
+    confirmVoid: "Void this validation?",
+    noPrograms: "You have no validation program bound to you — contact the administrator.",
+    // booth pay modal / receipts
+    gross: "Fee",
+    discount: "Discount",
+  },
   users: {
     title: "Users",
     add: "+ Add user",

apps/web/src/lib/i18n/sq.ts

@@ -68,6 +68,7 @@ export const sq = {
     logs: "Loget",
     backup: "Kopje rezervë",
     profile: "Profili",
+    validate: "Validime",
   },
   drawer: {
     stateTitle: "Arka tani",
@@ -235,6 +236,7 @@ export const sq = {
     evtCashOut: "PAGESË",
     evtCashReview: "SHQYRTIM",
     evtConfigChange: "KONFIG",
+    evtValidation: "VALIDIM",
     decision: { authorize: "autorizuar", deny: "refuzuar" },
     evtAnomaly: "ANOMALI",
     evtRefused: "REFUZUAR",
@@ -748,6 +750,51 @@ export const sq = {
     fieldPhone: "Telefoni",
     fieldEmail: "Email",
   },
+  // Merchant validations (bar / lavazh) — the /setup/site panel, the merchant's
+  // /validate screen, and the booth-modal discount lines. See validation-discounts.md.
+  val: {
+    // /setup/site
+    sectionTitle: "Validime tregtare",
+    sectionHint: "Shërbime të tjera brenda parkut (bar / lavazh) skanojnë biletën e hyrjes dhe bëjnë zbritje — pagesa dhe fatura bëhen në kabinë.",
+    enableBar: "Bar",
+    enableLavazh: "Lavazh",
+    labelName: "Etiketa në faturë",
+    labelNamePh: "p.sh. Lavazh — 1 orë falas",
+    mode: "Lloji i zbritjes",
+    modeComp: "Parkimi falas plotësisht",
+    modeTimeCredit: "Minutat e para falas",
+    modeFixed: "Zbritje shume (shkruhet në skanim)",
+    modePercent: "Zbritje në përqindje",
+    minutes: "Minuta falas",
+    percent: "Përqindja (%)",
+    maxAmount: "Tavani i zbritjes për validim",
+    maxPerDay: "Maks. validime në ditë (bosh = pa kufi)",
+    users: "Përdoruesit që validojnë",
+    usersHint: "Vetëm përdoruesit e zgjedhur (me lejen validation:create në rolin e tyre) mund të aplikojnë këtë program nga pajisja e tyre.",
+    noUsers: "Asnjë përdorues në sistem — krijojeni te Përdoruesit.",
+    saved: "U ruajt.",
+    // /validate (the merchant screen)
+    title: "Validim biletash",
+    scanPrompt: "Skanoni ose shkruani numrin e biletës",
+    lookup: "Kërko",
+    entry: "Hyrja:",
+    notFound: "Nuk u gjet biletë me këtë numër.",
+    closed: "Bileta është e mbyllur (ka dalë ose është anuluar).",
+    subscription: "Kjo është hyrje abonenti — nuk validohet.",
+    amountLabel: "Shuma e zbritjes",
+    amountHint: "maks. {{max}}",
+    apply: "Apliko validimin",
+    applied: "Validimi u aplikua.",
+    existing: "Validime në këtë biletë",
+    voided: "anuluar",
+    used: "përdorur në pagesë",
+    void: "Anulo",
+    confirmVoid: "Të anulohet ky validim?",
+    noPrograms: "Nuk keni asnjë program validimi të lidhur me ju — kontaktoni administratorin.",
+    // booth pay modal / receipts
+    gross: "Tarifa",
+    discount: "Zbritje",
+  },
   users: {
     title: "Përdoruesit",
     add: "+ Shto përdorues",

apps/web/src/router.tsx

@@ -46,6 +46,7 @@ import { DrawerManager } from "./DrawerManager.js";
 import { CARD_PAYMENTS_ENABLED } from "./lib/features.js";
 import { LogsViewer } from "./LogsViewer.js";
 import { BackupSettings } from "./BackupSettings.js";
+import { ValidateScreen } from "./ValidateScreen.js";
 import { RecycleBin } from "./RecycleBin.js";
 import { Profile } from "./Profile.js";
 // Reports pulls in Recharts (~heavy) — lazy-loaded so it stays OUT of the booth's
@@ -458,8 +459,11 @@ function RootLayout() {
       <header className="flex items-center gap-4 border-b border-term-border bg-term-panel px-4 py-2">
         <span className="text-sm font-bold uppercase tracking-widest text-term-amber">▮ Parking</span>
         <nav className="flex items-center gap-1">
-          <NavLink to="/booth" label={t("nav.booth")} />
-          <NavLink to="/shifts" label={t("nav.shifts")} />
+          {show("session:read") && <NavLink to="/booth" label={t("nav.booth")} />}
+          {show("shift:read") && <NavLink to="/shifts" label={t("nav.shifts")} />}
+          {/* The merchant's (bar/lavazh) scan-and-validate screen. Their typical role
+              grants ONLY validation:create, so this is often their whole nav. */}
+          {show("validation:create") && <NavLink to="/validate" label={t("nav.validate")} />}
           {/* Drawer — record cash movements (operator) / review them (admin). Shown if the
               user can do either. See wiki/concepts/shift.md. */}
           {(show("drawer:create") || show("drawer:review")) && (
@@ -523,7 +527,12 @@ function RootLayout() {
 const indexRoute = createRoute({
   getParentRoute: () => rootRoute,
   path: "/",
-  beforeLoad: () => {
+  beforeLoad: ({ context }) => {
+    // A merchant-only user (validation:create without the booth's session:read)
+    // lands on their scan-and-validate screen; everyone else on the booth.
+    if (can(context.user, "validation:create") && !can(context.user, "session:read")) {
+      throw redirect({ to: "/validate" });
+    }
     throw redirect({ to: "/booth" });
   },
 });
@@ -534,6 +543,20 @@ const boothRoute = createRoute({
   component: BoothScreen,
 });
 
+// The merchant (bar/lavazh) scan-and-validate screen — usually the ONLY page a
+// merchant user's role can reach. The server enforces the program↔user binding on
+// apply; this gate is defence in depth. See wiki/concepts/validation-discounts.md.
+const validateRoute = createRoute({
+  getParentRoute: () => rootRoute,
+  path: "/validate",
+  beforeLoad: ({ context }) => requirePerm("validation:create")(context),
+  component: function ValidateRoute() {
+    const { user } = rootRoute.useRouteContext();
+    if (!user) return null;
+    return <ValidateScreen user={user} />;
+  },
+});
+
 // Back-compat redirects for paths that moved. Most config screens live under /setup;
 // Subscriptions/Plans/Tariff-Lab were promoted OUT of /setup into the standalone
 // /subscriptions section (2026-06-21) — redirect the old /setup/* paths too so existing
@@ -779,6 +802,7 @@ const profileRoute = createRoute({
 const routeTree = rootRoute.addChildren([
   indexRoute,
   boothRoute,
+  validateRoute,
   ...legacyRedirects,
   profileRoute,
   shiftRoute,

apps/web/src/ui/event-detail.tsx

@@ -25,6 +25,7 @@ export const EVENT_STYLE: Record<string, { labelKey: string; color: string }> =
   cash_out: { labelKey: "booth.evtCashOut", color: "text-term-amber" },
   cash_review: { labelKey: "booth.evtCashReview", color: "text-term-cyan" },
   config_change: { labelKey: "booth.evtConfigChange", color: "text-term-amber" },
+  validation: { labelKey: "booth.evtValidation", color: "text-term-green" },
   anomaly: { labelKey: "booth.evtAnomaly", color: "text-term-red" },
 };