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]>

core/src/account/store.ts

@@ -0,0 +1,156 @@
+import type { EkklesiaUserId } from "@ekklesia/contracts";
+import { eq, sql } from "drizzle-orm";
+import { ekklesiaCoreUser } from "../identity/schema.js";
+import type { AccountDrizzleDatabase } from "./database.js";
+import {
+  type AccountPreferences,
+  type AccountPreferencesUpdate,
+  parseAccountPreferencesUpdate,
+  resolveAccountPreferences,
+} from "./preferences.js";
+import { ekklesiaCoreUserPreference } from "./schema.js";
+
+export type AccountStoreErrorCode =
+  | "ACCOUNT_NOT_FOUND"
+  | "ACCOUNT_PREFERENCES_INVALID"
+  | "ACCOUNT_READ_FAILED"
+  | "ACCOUNT_WRITE_FAILED";
+
+const accountStoreMessages: Readonly<Record<AccountStoreErrorCode, string>> = Object.freeze({
+  ACCOUNT_NOT_FOUND: "The account was not found.",
+  ACCOUNT_PREFERENCES_INVALID: "The preferences are not valid.",
+  ACCOUNT_READ_FAILED: "The account could not be read.",
+  ACCOUNT_WRITE_FAILED: "The preferences could not be saved.",
+});
+
+/** Never carries the underlying database error, SQL text, host, or stack — matching
+ * `DashboardStoreError` exactly. */
+export class AccountStoreError extends Error {
+  readonly code: AccountStoreErrorCode;
+
+  constructor(code: AccountStoreErrorCode) {
+    super(accountStoreMessages[code]);
+    this.name = "AccountStoreError";
+    this.code = code;
+    this.stack = `${this.name}: ${this.message}`;
+    Object.freeze(this);
+  }
+}
+
+/**
+ * What a signed-in person is shown about their own account: the name and email they signed up
+ * with, and their preferences. Deliberately nothing else — not the image URL, not verification
+ * state, not timestamps — so the one place the browser learns about an account carries exactly
+ * what the account area displays (ADR 0062).
+ */
+export interface AccountSummary {
+  readonly name: string;
+  readonly email: string;
+  readonly preferences: AccountPreferences;
+}
+
+/**
+ * A person's own account, and only their own: every method takes the one user id whose account it
+ * reads or writes, and the HTTP surface supplies it from the authenticated session, never from the
+ * request. There is no method that lists accounts or reads someone else's by any other key.
+ */
+export interface AccountStore {
+  /** The person's summary, or `undefined` when no such person exists. A person who never chose a
+   * preference gets the defaults. */
+  readAccount(userId: EkklesiaUserId): Promise<AccountSummary | undefined>;
+  /** Changes the named preferences and keeps the rest, returning everything now in effect. */
+  updatePreferences(
+    userId: EkklesiaUserId,
+    update: AccountPreferencesUpdate,
+  ): Promise<AccountPreferences>;
+}
+
+function rethrowAsStoreError(error: unknown, code: AccountStoreErrorCode): never {
+  if (error instanceof AccountStoreError) {
+    throw error;
+  }
+  throw new AccountStoreError(code);
+}
+
+/**
+ * Core's persistence for a person's own account summary and preferences.
+ *
+ * Validation lives here as well as at the HTTP boundary, so the invariants hold for any caller: an
+ * update is re-read through the same strict parser, and a preference row can only be written for a
+ * person who exists.
+ */
+export function createAccountStore(db: AccountDrizzleDatabase): AccountStore {
+  return Object.freeze({
+    async readAccount(userId: EkklesiaUserId): Promise<AccountSummary | undefined> {
+      try {
+        const rows = await db
+          .select({
+            appearance: ekklesiaCoreUserPreference.appearance,
+            email: ekklesiaCoreUser.email,
+            motion: ekklesiaCoreUserPreference.motion,
+            name: ekklesiaCoreUser.name,
+          })
+          .from(ekklesiaCoreUser)
+          .leftJoin(
+            ekklesiaCoreUserPreference,
+            eq(ekklesiaCoreUserPreference.userId, ekklesiaCoreUser.id),
+          )
+          .where(eq(ekklesiaCoreUser.id, userId))
+          .limit(1);
+        const row = rows[0];
+        if (!row) {
+          return undefined;
+        }
+        return Object.freeze({
+          email: row.email,
+          name: row.name,
+          preferences: resolveAccountPreferences(row),
+        });
+      } catch (error) {
+        rethrowAsStoreError(error, "ACCOUNT_READ_FAILED");
+      }
+    },
+
+    async updatePreferences(
+      userId: EkklesiaUserId,
+      update: AccountPreferencesUpdate,
+    ): Promise<AccountPreferences> {
+      const parsed = parseAccountPreferencesUpdate(update);
+      if (parsed === undefined) {
+        throw new AccountStoreError("ACCOUNT_PREFERENCES_INVALID");
+      }
+      try {
+        return await db.transaction(async (tx) => {
+          // Checked inside the transaction rather than left to the foreign key, so a person who
+          // does not exist is a clear "not found" instead of a constraint failure.
+          const people = await tx
+            .select({ id: ekklesiaCoreUser.id })
+            .from(ekklesiaCoreUser)
+            .where(eq(ekklesiaCoreUser.id, userId))
+            .limit(1);
+          if (people.length === 0) {
+            throw new AccountStoreError("ACCOUNT_NOT_FOUND");
+          }
+          const rows = await tx
+            .insert(ekklesiaCoreUserPreference)
+            .values({ userId, ...parsed })
+            .onConflictDoUpdate({
+              set: { ...parsed, updatedAt: sql`now()` },
+              target: ekklesiaCoreUserPreference.userId,
+            })
+            .returning({
+              appearance: ekklesiaCoreUserPreference.appearance,
+              motion: ekklesiaCoreUserPreference.motion,
+            });
+          const row = rows[0];
+          if (!row) {
+            throw new AccountStoreError("ACCOUNT_WRITE_FAILED");
+          }
+          return resolveAccountPreferences(row);
+        });
+      } catch (error) {
+        rethrowAsStoreError(error, "ACCOUNT_WRITE_FAILED");
+      }
+    },
+  });
+}