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 <[email protected]>

backend/app/schemas/schedule.py

@@ -1,5 +1,6 @@
 from datetime import time
 from pydantic import BaseModel
+from app.schemas.subject import SubjectOut
 
 
 class ScheduleBlockCreate(BaseModel):
@@ -25,6 +26,7 @@ class ScheduleBlockUpdate(BaseModel):
 class ScheduleBlockOut(BaseModel):
     id: int
     subject_id: int | None
+    subject: SubjectOut | None = None
     time_start: time
     time_end: time
     duration_minutes: int | None