feat(tariff-lab): DB-backed draft tariffs + named published versions

Experimenting used to mean publishing — churning the immutable version
history and risking real tickets pricing against a half-baked card while
the admin iterated. The lab is now a true sandbox:

- tariff_drafts table (migration 0021): MUTABLE by design — the one
  exception to "editing publishes a version"; a draft prices nothing and
  signs nothing. Drafts are validated + tz-stamped on save exactly like a
  publish, so a saved draft always simulates and never fails at publish.
- CRUD under /api/tariff/drafts (list tariff:read, mutations
  tariff:update); publishing a draft goes through the normal immutable
  POST /api/tariff/versions path.
- Lab UI rebuilt: sidebar lists lab drafts AND the full published history
  (click any to price against it); main pane cut to pure entry/exit
  (ticket loader, payment, category inputs dropped); the composer form is
  extracted to TariffEditorForm.tsx and reused in a modal (new drafts
  prefill from the active card); per-draft Publish with confirm.
- tariff_versions.name (migration 0022): optional label stamped at
  publish — carried from the lab draft, or typed in the composer's new
  optional field — so history reads "Winter 2027", not UUID prefixes.
- Includes the composer UI + sq/en labels for the package mode (engine
  landed in d9e6c13) and the "Flat price / hour" relabel.

5 new server integration tests (RBAC, roundtrip, validation, tz-stamp +
simulate + publish w/ name); server suite 288 green.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

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

@@ -319,25 +319,30 @@ export const en: Catalog = {
     bandDuration: "Band duration",
     hoursUnit: "hours",
     egHours: "e.g. 2",
-    pricePerIncrement: "Price / increment",
+    pricePerIncrement: "Price / increment (per hour)",
     thereafter: "thereafter (open-ended)",
     remove: "Remove",
     addBlock: "+ Add block",
     publishNewVersion: "Publish new version",
     publishing: "Publishing…",
+    versionNamePh: "Version name (optional), e.g. Summer 2026",
     publishedOk: "New tariff version published — it's now the active rate.",
     defaultCard: "Base rate (always active)",
     defaultCardHint: "The base rate applied when no time/seasonal tier matches. This alone is enough for most car parks.",
     modeLadder: "Hourly ladder",
-    modeFlat: "Flat price",
+    modeFlat: "Flat price / hour",
     modeStepped: "By duration (up-to)",
+    modePackage: "Window package (one total)",
+    packageHint:
+      "ONE total for any presence inside this tier's window — leaving earlier costs the same. Touching the window on two different nights charges the package twice (once per night). Hours outside the window are priced by the base rate.",
+    packageTotal: "Package total",
     steppedHint:
       "Set the TOTAL price for a stay up to a given time (e.g. up to 3h = 500). The first row whose limit ≥ the duration wins (the limit is inclusive). The last row's total repeats as a per-day price for longer stays.",
     stepUpTo: "Up to",
     stepTotal: "Total price",
     addStep: "+ Add row",
     steppedTiersConflict:
-      "⚠ Time/seasonal tiers do NOT apply when the base rate is 'By duration (up-to)' — the engine ignores them entirely. Remove the tiers, or switch the base rate to 'Hourly ladder' or 'Flat price'. Publishing is blocked until this is fixed.",
+      "⚠ Time/seasonal tiers do NOT apply when the base rate is 'By duration (up-to)' — the engine ignores them entirely. Remove the tiers, or switch the base rate to 'Hourly ladder' or 'Flat price / hour'. Publishing is blocked until this is fixed.",
     tiersAdvanced: "Advanced: time & seasonal tiers",
     tiersHint: "Optional. Add tiers that apply only at certain hours/days/dates or for a category (e.g. happy hour, night rate, weekend, bus). With no tiers, just the base rate is published.",
     tierName: "Name",
@@ -513,21 +518,26 @@ export const en: Catalog = {
   lab: {
     title: "Tariff Lab",
     intro:
-      "Test rates in time (day/night windows, daily caps, overstay) in seconds, with no waiting. Pricing uses the same logic as the booth; nothing is written to the ledger.",
-    loadTicket: "Load from a real ticket",
-    loadTicketPh: "Ticket number / identity",
-    load: "Load",
-    loaded: "Loaded session {{id}}",
-    tariffVersion: "Tariff version",
-    activeVersion: "Active version (current)",
+      "Compose experimental rate cards and price hypothetical stays against them — nothing goes live until you publish. Pricing uses the same logic as the booth; nothing is written to the ledger.",
+    drafts: "Lab tariffs",
+    newDraft: "New draft",
+    activeTariff: "Active tariff",
+    published: "Published versions",
+    noDrafts: "No lab tariffs yet — create a draft to experiment.",
+    edit: "Edit",
+    publish: "Publish",
+    delete: "Delete",
+    draftName: "Name",
+    draftNamePh: "e.g. Winter proposal",
+    saveDraft: "Save draft",
+    savingDraft: "Saving…",
+    newDraftTitle: "New lab tariff",
+    editDraftTitle: "Edit lab tariff",
+    confirmPublish: 'Publish "{{name}}" as the new live rate card? It takes effect immediately.',
+    confirmDelete: 'Delete lab tariff "{{name}}"?',
     entered: "Entered",
-    asOf: "As of (now/exit)",
+    exit: "Exit",
     now: "Now",
-    category: "Category",
-    categoryPh: "e.g. bus (blank = car)",
-    payment: "Payment",
-    paid: "paid",
-    graceMin: "grace (min)",
     price: "Compute price",
     pricing: "Pricing…",
     outcome: "Outcome",