Implement activity log (task 22)

- activity_log table in _core/schema.ts with household+created_at index;
  migration 0008_activity_log.sql applied
- logActivity() in _core/activity.ts reads current session and inserts a row
- ActivityLogEntry type + renderActivity?(entry): string added to
  EntityTypeRegistration so modules declare human-readable labels without
  any if/else branches in the widget
- core.activity widget replaced with a real async server component that
  queries the last 20 rows and renders via the registry
- logActivity wired into every create/update/delete in calendar, lists,
  and notes server actions; getAuthorizedItem also returns text so
  toggle/delete can include item text in the payload
- pnpm typecheck, lint, build, and all 4 E2E specs pass

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/modules/calendar/manifest.tsx

@@ -101,6 +101,12 @@ const manifest: ModuleManifest = {
       share: { canShare: true, defaultCapabilities: ["read"] },
       search: { search: searchCalendars },
       resolveUrl: (id) => `/calendar?id=${id}`,
+      renderActivity: (entry) => {
+        const name = entry.payload?.name as string | undefined;
+        if (entry.action === "create") return `Created calendar${name ? ` "${name}"` : ""}`;
+        if (entry.action === "delete") return "Deleted calendar";
+        return `Updated calendar${name ? ` "${name}"` : ""}`;
+      },
     },
     {
       type: "calendar.event",
@@ -109,6 +115,12 @@ const manifest: ModuleManifest = {
       reminder: { canRemind: true },
       search: { search: searchEvents },
       resolveUrl: (id) => `/calendar/events/${id}`,
+      renderActivity: (entry) => {
+        const title = entry.payload?.title as string | undefined;
+        if (entry.action === "create") return `Created event${title ? ` "${title}"` : ""}`;
+        if (entry.action === "delete") return "Deleted event";
+        return `Updated event${title ? ` "${title}"` : ""}`;
+      },
     },
   ],
   dashboardWidgets: [