feat(page): temporary notes — auto-trash after X hours unless made permanent (#201)

"Temporary notes" with a death timer: created via a dedicated hourglass button
in the space-tree header, a note auto-moves to Trash after a configurable X
hours (default 24) unless explicitly made permanent ("structure or die").

Reuses existing mechanisms, mirroring is_template and the trash-cleanup job:
- New nullable column pages.temporary_expires_at (NULL = permanent; non-NULL =
  frozen deadline) + partial index for the sweep; workspace column
  temporary_note_hours (default via DEFAULT_TEMPORARY_NOTE_HOURS = 24).
- create-page DTO `temporary` flag; the deadline is frozen at creation so later
  setting changes never reschedule existing notes.
- POST /pages/toggle-temporary (mirror of toggle-template): arm/clear the timer,
  CASL-guarded via validateCanEdit, cross-workspace NotFound defense-in-depth.
- TemporaryNoteCleanupService: hourly @Interval sweep that soft-deletes expired
  notes through the exact PageRepo.removePage path (recursive over children,
  emits PAGE_SOFT_DELETED), attributed to the creator; idempotent via
  deletedAt IS NULL filters.
- restorePage clears temporary_expires_at so a restored note can't be re-trashed.
- Workspace setting temporary_note_hours (audit-tracked) + a hours editor in
  workspace General settings.
- Client: second create button, orange tree icon, tree + page-header menu toggle
  ("Make temporary"/"Make permanent"), an open-note banner with a rescue action,
  and en/ru i18n.

Tests (unit): toggle-temporary controller (toggle/explicit/permission/cross-ws +
DTO validation), cleanup-job sweep (selection filters, per-note removePage,
error isolation), and a migration up/down sanity. Server tsc, client tsc -b,
and the page+workspace jest suites are green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/client/src/features/editor/full-editor.tsx

@@ -26,6 +26,7 @@ import { FixedToolbar } from "@/features/editor/components/fixed-toolbar/fixed-t
 import { PageEditMode } from "@/features/user/types/user.types.ts";
 import { useAsideTriggerProps } from "@/hooks/use-toggle-aside.tsx";
 import { DeletedPageBanner } from "@/features/page/trash/components/deleted-page-banner.tsx";
+import { TemporaryNoteBanner } from "@/features/page/components/temporary-note-banner.tsx";
 import clsx from "clsx";
 import {
   currentPageEditModeAtom,
@@ -37,6 +38,7 @@ const MemoizedTitleEditor = React.memo(TitleEditor);
 const MemoizedPageEditor = React.memo(PageEditor);
 const MemoizedFixedToolbar = React.memo(FixedToolbar);
 const MemoizedDeletedPageBanner = React.memo(DeletedPageBanner);
+const MemoizedTemporaryNoteBanner = React.memo(TemporaryNoteBanner);
 
 type PageUser = {
   id: string;
@@ -103,6 +105,7 @@ export function FullEditor({
         <MemoizedFixedToolbar />
       )}
       <MemoizedDeletedPageBanner slugId={slugId} />
+      <MemoizedTemporaryNoteBanner slugId={slugId} />
       <MemoizedTitleEditor
         pageId={pageId}
         slugId={slugId}