Task #164: Per-user notification preferences for Executive Meetings

Lets each user choose whether to receive in-app and/or email notifications
for each executive-meeting event type (meeting_created, request_submitted,
request_approved/rejected/needs_edit, task_assigned, task_completed).
Defaults to "everything on" when no preference row exists, preserving the
prior fan-out behavior for users who never visit the new UI.

Schema:
- New executive_meeting_notification_prefs table (user_id FK CASCADE,
  notification_type varchar(64), in_app bool default true, email bool
  default true, plus a unique index on (user_id, notification_type)).
- Pushed to dev DB via `pnpm --filter @workspace/db push`.

Backend:
- Exported EXECUTIVE_MEETING_NOTIFICATION_TYPES (canonical list) +
  filterRecipientsByNotificationPref(ids, type, channel) helper that
  returns only recipients whose row says the channel is on (default-on
  semantics for missing rows).
- recordExecutiveMeetingNotifications now filters recipients by
  channel="inApp" before inserting; sendExecutiveMeetingEmail filters
  by channel="email" before SMTP delivery.
- New endpoints under /executive-meetings/notification-prefs:
  GET → { types, prefs } merged with defaults.
  PUT → upserts each supplied (type, channel) pair via
  onConflictDoUpdate inside a transaction.

Frontend:
- New NotificationPrefsCard at the top of the Notifications section in
  artifacts/tx-os/src/pages/executive-meetings.tsx. Renders a Switch per
  (event type × channel) with batched save, dirty-state tracking, reset
  button, and useToast feedback.
- Translation keys for the card added to en.json and ar.json under
  executiveMeetings.notificationsPage.prefs.

Tests:
- 5 new tests in artifacts/api-server/tests/executive-meetings.test.mjs:
  GET defaults, PUT roundtrip + upsert, 400 on unknown type, in-app
  fan-out filtering (muted approver gets no row, control approver still
  does), and channel-independence (muting only the email channel leaves
  in-app delivery intact while persisting email=false in the DB row that
  sendExecutiveMeetingEmail's filter reads).
- All 36 executive-meetings tests pass. Full suite shows only one
  pre-existing flaky test elsewhere (groups-crud count assertion),
  unrelated to these changes.
- Added e2e UI test that logs in as admin, toggles a preference, saves,
  refreshes, and confirms persistence.
- After-hook cleans up new prefs rows for created users.

Follow-ups proposed: #236 (one-click reset to defaults), #237 (admin
view/override of any user's prefs).

Replit-Task-Id: 284ce15d-40d7-447e-90ca-090b44d8227b

lib/db/src/schema/executive-meetings.ts

@@ -8,6 +8,7 @@ import {
   date,
   time,
   jsonb,
+  boolean,
   index,
   uniqueIndex,
 } from "drizzle-orm/pg-core";
@@ -163,6 +164,52 @@ export const executiveMeetingNotificationsTable = pgTable(
   },
 );
 
+/**
+ * Per-user notification preferences for the Executive Meetings module.
+ *
+ * Each row toggles a single (userId, notificationType) pair on or off
+ * for the in-app bell channel and the email channel independently.
+ *
+ * Default behaviour when no row exists: BOTH channels ON. This keeps the
+ * legacy "fan out to everyone, every time" semantics intact for users
+ * who never visit the preferences UI. Only an explicit opt-out (row
+ * present + flag set to false) suppresses delivery.
+ *
+ * notificationType mirrors the keys passed to
+ * `recordExecutiveMeetingNotifications` / `sendExecutiveMeetingEmail`:
+ *   - meeting_created
+ *   - request_submitted
+ *   - request_approved
+ *   - request_rejected
+ *   - request_needs_edit
+ *   - task_assigned
+ *   - task_completed
+ */
+export const executiveMeetingNotificationPrefsTable = pgTable(
+  "executive_meeting_notification_prefs",
+  {
+    id: serial("id").primaryKey(),
+    userId: integer("user_id")
+      .notNull()
+      .references(() => usersTable.id, { onDelete: "cascade" }),
+    notificationType: varchar("notification_type", { length: 64 }).notNull(),
+    inApp: boolean("in_app").notNull().default(true),
+    email: boolean("email").notNull().default(true),
+    createdAt: timestamp("created_at", { withTimezone: true })
+      .notNull()
+      .defaultNow(),
+    updatedAt: timestamp("updated_at", { withTimezone: true })
+      .notNull()
+      .defaultNow()
+      .$onUpdate(() => new Date()),
+  },
+  (t) => ({
+    userTypeUnique: uniqueIndex(
+      "executive_meeting_notification_prefs_user_type_unique",
+    ).on(t.userId, t.notificationType),
+  }),
+);
+
 export const executiveMeetingAuditLogsTable = pgTable(
   "executive_meeting_audit_logs",
   {