feat(shell): make module pages first-class top-level routes

Module pages move from `/modules/<id>` to `/<module-id>` (`/signage`),
beside `/settings` and `/account`, so the implementation concept
"module" never appears in a user-facing address. ADR 0057 is rewritten
to match.

- Core reserves the top-level names the platform actually serves today
  (`account`, `api`, `assets`, `display`, `settings`), and discovery
  refuses a module that declares one with `MODULE_ID_RESERVED`. That
  covers startup, `modules:validate`, and package verification. Tests in
  `apps/api` hold the set to every top-level route the API registers and
  every page the shell interprets.
- The API serves the Dashboard page at `/<module-id>` and below only for
  modules discovered with a Dashboard UI, enabled or not: a disabled
  module's bookmark still opens the Dashboard, which says it is
  unavailable. An arbitrary root path such as
  `/definitely-not-a-real-module` stays the sanitized 404.
- Both reference proxies forward every top-level path shaped like a
  module id and let the API decide; the split Dashboard hostname still
  refuses `/api`, `/display`, and `/assets`. Installing a module needs no
  proxy change.
- `/<module-id>/<page>` is already served and forwarded, so a later
  module sub-page contract needs no routing or deployment change; the
  shell shows "Page not found" there until it exists.
- The deploy smoke checks a module's address before install, while
  installed, while disabled, after removal, and after reinstall, plus
  unknown names and the old `/modules/…` form through the real proxy.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/api/src/app.ts

@@ -363,10 +363,18 @@ export function createApiApp(options: CreateApiAppOptions): Hono {
   // own entirely. See `./health-routes.js`.
   app.route("/", createHealthRoutes(options.health));
 
-  // The Dashboard page and its one script, at exact literal paths outside `/api/` (ADR 0044). They
-  // grant no authority and resolve no principal; the page asks `/api/v1/principal` itself. See
-  // `./dashboard-host-routes.js`.
-  app.route("/", createDashboardHostRoutes(options.dashboardHostAssets));
+  // The Dashboard page and its one script, at fixed paths outside `/api/` (ADR 0044, ADR 0057): the
+  // page at `/`, the Dashboard's platform pages, and every discovered module with a Dashboard UI at
+  // `/<module-id>`. They grant no authority and resolve no principal; the page asks
+  // `/api/v1/principal` itself. See `./dashboard-host-routes.js`.
+  app.route(
+    "/",
+    createDashboardHostRoutes(options.dashboardHostAssets, {
+      modulePages: options.moduleLifecycle.snapshot.discoveredModules
+        .filter((module) => module.entrypoints.ui !== undefined)
+        .map((module) => module.manifest.id),
+    }),
+  );
 
   app.route(
     "/",