Add subject options and redesign TV dashboard layout

Subject options:
- New subject_options table (auto-created on startup)
- SubjectOut now includes options list; all eager-loading chains updated
- Admin: Options panel per subject with add, inline edit, and delete
- WS broadcast and dashboard API include options in block subject data

TV dashboard:
- Three equal columns: Timer | Activities | Schedule
- Activities column shows current subject's options in large readable text
- Activities area has subject-colored border and tinted background
- Subject name and label displayed correctly using embedded subject data

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

backend/app/models/__init__.py

@@ -2,7 +2,7 @@
 from app.models.base import Base, TimestampMixin
 from app.models.user import User
 from app.models.child import Child
-from app.models.subject import Subject
+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
@@ -13,6 +13,7 @@ __all__ = [
     "User",
     "Child",
     "Subject",
+    "SubjectOption",
     "ScheduleTemplate",
     "ScheduleBlock",
     "DailySession",