Add the account area and account-synced Appearance preferences

Stage 1 PR 6 (ADR 0062). /account shows who is signed in; /account/appearance
chooses System, Light, or Dark and reduced motion (System, Reduce, Allow).

- Core: ekklesia_core_user_preference, one typed, CHECK-constrained,
  nullable column per preference (null = never chosen), migration
  0008_user_preferences (additive), @ekklesia/core/account store, and the
  authenticated-baseline permission core.account.self.manage.
- API: GET /api/v1/account (name, email, preferences) and partial
  PATCH /api/v1/account/preferences, self-only by construction: no user id
  is accepted anywhere; trusted Origin and body limit on the mutation.
- Shell: the account control shows name, email, and initials (never the
  unvetted image URL) and offers Account, Appearance, Sign out; native
  radio groups apply a choice at once through the ADR 0060 controller and
  save it; the server's answer wins and a failed save reverts.
- First paint: a classic, same-origin, render-blocking appearance.js in
  <head> applies a two-word localStorage cache before paint (no inline
  script, CSP unchanged). The account replaces the cache on every load,
  sign-out clears it, and other tabs follow via the storage event.
- Deploy smoke: real-Chromium checks for light/dark, OS emulation,
  overrides, reload persistence, pre-paint, Shadow DOM modules, reduced
  motion, the display staying light, and phone width; the browser
  container gets a 512 MiB /dev/shm so a long session no longer fails
  requests with ERR_INSUFFICIENT_RESOURCES.

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

apps/api/src/dashboard-host-routes.ts

@@ -17,6 +17,8 @@ import { createDashboardHostAssets, type DashboardHostAssets } from "./dashboard
  */
 export const DASHBOARD_HOST_PAGE_PATH = "/";
 export const DASHBOARD_HOST_SCRIPT_PATH = "/assets/ekklesia-dashboard/app.js";
+/** The pre-paint appearance script (ADR 0062), beside the application script. */
+export const DASHBOARD_HOST_APPEARANCE_SCRIPT_PATH = "/assets/ekklesia-dashboard/appearance.js";
 
 /**
  * Revalidate-always with a strong `ETag`, exactly the module UI and display-host script policy. The
@@ -56,8 +58,12 @@ export class DashboardHostConfigurationError extends Error {
  * a composition can never pair bytes with a validator computed from different bytes. */
 function snapshotAssets(input: DashboardHostAssets): DashboardHostAssets {
   try {
-    const snapshot = createDashboardHostAssets(input.html, input.script);
-    if (snapshot.htmlEtag !== input.htmlEtag || snapshot.scriptEtag !== input.scriptEtag) {
+    const snapshot = createDashboardHostAssets(input.html, input.script, input.appearanceScript);
+    if (
+      snapshot.htmlEtag !== input.htmlEtag ||
+      snapshot.scriptEtag !== input.scriptEtag ||
+      snapshot.appearanceScriptEtag !== input.appearanceScriptEtag
+    ) {
       throw new DashboardHostConfigurationError();
     }
     return snapshot;
@@ -169,5 +175,17 @@ export function createDashboardHostRoutes(
     ),
   );
 
+  // Same-origin, revalidated like the application script, and carrying nothing but code: the
+  // person's cached choice lives in their browser and is read by this script, never served by it.
+  routes.get(DASHBOARD_HOST_APPEARANCE_SCRIPT_PATH, (c) =>
+    fixedAsset(
+      c.req.header("if-none-match"),
+      snapshot.appearanceScript,
+      snapshot.appearanceScriptEtag,
+      "text/javascript; charset=utf-8",
+      {},
+    ),
+  );
+
   return routes;
 }