feat(kanban): archive automatico para cards Done +30 dias (issue 0092)

Adds an archive layer separate from the trash. Cards in is_done columns
that have been there for more than 30 days are auto-archived on the next
board load (throttled to once every 30 minutes). Archived cards leave
the board but stay in the DB and are listed in a new sidebar drawer
"Hecho (archivo)" below the existing Papelera, with a one-click restore.

Schema (migration 012_card_archived.sql):
- ALTER TABLE cards ADD COLUMN archived_at TEXT;
- NULL = active, ISO timestamp = archived. Independent from deleted_at.

Backend:
- Card.ArchivedAt + JSON; ListCardsWithTime filters archived_at IS NULL.
- New methods: ArchiveCard, UnarchiveCard, ListArchivedCards,
  AutoArchiveDoneOlderThan.
- New endpoints: GET /api/archive, POST /api/cards/:id/archive,
  POST /api/cards/:id/unarchive.
- handleGetBoard invokes maybeAutoArchive (atomic throttle, 30 min sweep,
  30 day cutoff). Errors logged but never block the board response.

Frontend:
- Card type + api.ts add the new field and helpers.
- App.tsx state for archive list, reload, archive/unarchive handlers.
- New sidebar drawer with toggle, count badge, restore button.
- KanbanCard gains an "Archivar" menu item (gated on isDone +
  onArchive prop) for manual archiving of any done card.

Tests:
- Playwright e2e/archive.spec.ts: manual archive via menu, drawer
  toggle, unarchive. Picks a done card via /api/board introspection so
  it stays stable regardless of board state.
- Auto-archive of >30d cards: not under e2e (real time travel needed);
  covered by code review of the SQL query and the throttle.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/KanbanColumn.tsx

@@ -82,6 +82,7 @@ interface Props {
   onAssignCard: (id: string, assignee_id: string | null) => void;
   onSetCardDeadline?: (id: string, deadline: string | null) => void;
   onSetRequester?: (id: string, requester: string) => void;
+  onArchiveCard?: (id: string) => void;
   requesterOptions?: string[];
   onOpenCustomCardColor?: (cardId: string, current: string) => void;
   activeSticker?: string | null;
@@ -117,6 +118,7 @@ function KanbanColumnImpl({
   onAssignCard,
   onSetCardDeadline,
   onSetRequester,
+  onArchiveCard,
   requesterOptions,
   onOpenCustomCardColor,
   activeSticker,
@@ -593,6 +595,7 @@ function KanbanColumnImpl({
                     onAssign={onAssignCard}
                     onSetDeadline={onSetCardDeadline}
                     onSetRequester={onSetRequester}
+                    onArchive={onArchiveCard}
                     requesterOptions={requesterOptions}
                     onOpenCustomColor={onOpenCustomCardColor}
                     users={users}