feat(modules): venue-module registry — entitled ∩ activated, requireModule, Setup panel

Groundwork for the Car Wash pilot (wiki/decisions/venue-modules.md, build-order
steps 1 + 3). No Car Wash code yet; validation is the first module behind the
seam, unchanged in behaviour.

- @parking/shared: MODULE_IDS, ModuleManifest, MODULES (parking required;
  validation dependsOn parking), parseEntitledModules / resolveModuleActivation
  / effectiveModules as pure functions.
- DB: site_config.modules_json (migration 0026, hand-written + journal;
  additive, nullable = everything entitled).
- Server: modules.ts (entitledModules from MODULES_ENTITLED env, activated
  from site_config, effective set, requireModule preHandler → 403
  module_disabled); modules/index.ts registers folder-based modules by
  iterating the registry (modules/validation); site-config GET exposes
  modules/modulesEntitled/modulesActivated, PUT takes the full desired set,
  enforces entitlement + dependency rules (400 with reason) and signs one
  config_change per module that actually flips; /api/auth/me carries the
  effective set; validation routes guarded requireModule → requirePermission.
- Web: lib/modules.ts + modules/{index,validation}; router.tsx spreads
  WEB_MODULES into nav + route tree (validate route no longer named there);
  Setup → Site "Modules" panel (required shown disabled, dependencies as
  hints, server refusal shown verbatim); validation sections + programs fetch
  gated on the module; App invalidates the router whenever the session
  changes (route-context consumers only re-read on navigation — the nav was
  stale after a flip, and after every other setUser too).
- Lavazh validation station retired (STATIONS = ["bar"]; rows untouched).
- Deploy: MODULES_ENTITLED=parking,validation explicit in both booth stacks;
  documented in .env.example.
- Tests: modules.test.ts (7); suite 329/329; web build clean; Playwright
  round-trip on /setup/site verified live.

Claude-Session: https://claude.ai/code/session_01FWncR69HgGPuei1dLrW3cU

apps/server/src/modules/index.ts

@@ -0,0 +1,51 @@
+import type { FastifyInstance } from "fastify";
+import type { Db } from "@parking/db";
+import { MODULES, parseEntitledModules, type ModuleId } from "@parking/shared";
+import type { EventLog } from "../event-log.js";
+import { effectiveModulesFor } from "../modules.js";
+import { validationModule } from "./validation/index.js";
+
+// The server-side module registry. A module's routes live in its own folder
+// (apps/server/src/modules/<id>/index.ts) and are registered by iterating
+// @parking/shared's MODULES — so adding a module is one manifest entry + one folder +
+// one line in SERVER_MODULES below, with nothing else in the core touched
+// (wiki/decisions/venue-modules.md, "A module = a manifest + three folders").
+//
+// `parking` is registered in the manifest but has NO folder yet: its routes are still
+// the flat list in server.ts. That is deliberate — the seam is drawn, the code moves
+// across it subsystem by subsystem as each is touched, not in one big move.
+
+export interface ServerModuleDeps {
+  db: Db;
+  eventLog: EventLog;
+}
+
+export interface ServerModule {
+  id: ModuleId;
+  register(app: FastifyInstance, deps: ServerModuleDeps): Promise<void>;
+}
+
+const SERVER_MODULES: Partial<Record<ModuleId, ServerModule>> = {
+  validation: validationModule,
+};
+
+/** Register every folder-based module in registry order, then log what this site
+ *  is entitled to / has effective, so a "why is X missing" question is answerable
+ *  from the container log alone. */
+export async function registerModules(app: FastifyInstance, deps: ServerModuleDeps): Promise<void> {
+  for (const manifest of MODULES) {
+    const impl = SERVER_MODULES[manifest.id];
+    if (impl) {
+      if (impl.id !== manifest.id) throw new Error(`module registry mismatch: ${impl.id} registered under ${manifest.id}`);
+      await impl.register(app, deps);
+    }
+  }
+  const { entitled, unknown } = parseEntitledModules(process.env.MODULES_ENTITLED);
+  if (unknown.length > 0) {
+    app.log.warn({ unknown }, "MODULES_ENTITLED names unknown module ids — ignored");
+  }
+  app.log.info(
+    { entitled, effective: effectiveModulesFor(deps.db) },
+    "venue modules (entitled = MODULES_ENTITLED env; effective = entitled ∩ site activation)",
+  );
+}

apps/server/src/modules/validation/index.ts

@@ -0,0 +1,13 @@
+import { validationRoutes } from "../../routes/validations.js";
+import type { ServerModule } from "../index.js";
+
+// Merchant-scan ticket validation as a venue module. Kept for the Bar until a Bar
+// module absorbs it (wiki/decisions/venue-modules.md, decision 1). The routes
+// themselves still live in routes/validations.ts (unchanged location, now guarded by
+// requireModule("validation")); this folder is the registry hook.
+export const validationModule: ServerModule = {
+  id: "validation",
+  async register(app, { db, eventLog }) {
+    await validationRoutes(app, db, eventLog);
+  },
+};