Add Morning Routine to Admin and TV greeting state

Adds a per-user Morning Routine item list that appears in the TV
dashboard Activities panel during the "Good Morning" countdown
(before the first block starts).

- morning_routine_items table (auto-created on startup)
- CRUD API at /api/morning-routine (auth-required)
- Items included in the public DashboardSnapshot so TV gets them
  without auth
- Morning Routine section in Admin page (same add/edit/delete UX
  as subject options)
- TV Activities column shows routine items when no block is active,
  switches to subject options once a block starts

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

backend/app/models/__init__.py

@@ -6,6 +6,7 @@ from app.models.subject import Subject, SubjectOption
 from app.models.schedule import ScheduleTemplate, ScheduleBlock
 from app.models.session import DailySession, TimerEvent, TimerEventType
 from app.models.activity import ActivityLog
+from app.models.morning_routine import MorningRoutineItem
 from app.models.strike import StrikeEvent
 
 __all__ = [
@@ -21,5 +22,6 @@ __all__ = [
     "TimerEvent",
     "TimerEventType",
     "ActivityLog",
+    "MorningRoutineItem",
     "StrikeEvent",
 ]