feat(ui): Mission Control Recent Sessions mit verschachtelten Handoffs

Neue Tabelle mission_control_sessions (Migration AddMissionControlSessions), befuellt vom
InteractiveLaunchSpecService bei Task-, Ad-hoc- und Handoff-Kacheln. Flyout im Mission-Control-Header
listet die letzten 14 Tage / 50 Sessions, Handoffs eingerueckt unter ihrer Ursprungs-Session, mit
Fortsetzen (--resume im gespeicherten cwd) und Brief anzeigen.

src/ClaudeDo.Data/CLAUDE.md

@@ -24,6 +24,7 @@ Shared data layer: models, repositories, SQLite infrastructure, and git operatio
 - **WeekReportEntity** — Id, StartDate/EndDate (DateOnly), Markdown, GeneratedAt → `week_reports`, unique index on (start_date, end_date)
 - **TaskAttachmentEntity** — Id, TaskId (FK, ON DELETE CASCADE), FileName, ByteSize, CreatedAt → `task_attachments`
 - **TaskDependencyEntity** — one declared "run after" edge: TaskId + DependsOnTaskId, composite PK, table `task_dependencies`. Both FKs are `ON DELETE CASCADE`, which is what the old single `depends_on_task_id` column got from `ON DELETE SET NULL`: deleting a predecessor drops the edge so the dependent becomes pickable instead of blocked on a task that's gone. Written **only** by `TaskStateService.SetDependsOnAsync`.
+- **MissionControlSessionEntity** — SessionId (PK), Cwd, TaskId (no FK), Title, StartedAt, PredecessorSessionId, BriefPath → `mission_control_sessions`. Index behind Mission Control's "Recent sessions" flyout; written only by `InteractiveLaunchSpecService` (task/ad-hoc/handoff tile launches), insert-if-absent → [conpty-sessions](../../docs/explore-notes/conpty-sessions.md).
 - **SubtaskEntity**, **AgentInfo** — subtasks / record for scanned agent files
 
 ### AppSettingsEntity
@@ -120,6 +121,7 @@ Tables (one per line so parallel migrations don't collide on the same line):
 - `task_attachments`
 - `task_dependencies`
 - `list_folders`
+- `mission_control_sessions`
 
 Managed by EF Core migrations in `Migrations/`. **The 40 incremental migrations were squashed into
 a single `20260826094154_InitialCreate` on 2026-08-26** — the schema history is git history now,