Remove Programs tab and all supporting code

The Programs feature is superseded by Shows, which provides a more
flexible model with schedule slots. This commit removes all Programs
code across frontend and backend:

Frontend:
- Delete admin-program-form component (ts/html/scss)
- Delete program.service.ts and program.ts interface
- Remove Programs tab, form modal, and all CRUD logic from admin
  component (ts + html)

Backend:
- Delete programs API router
- Remove Program ORM model and ProgramCreate/Update/Response schemas
- Remove programs router registration from main.py
- Remove Program from seed data, seed helpers, and truncate/reset

backend/app/main.py

@@ -8,9 +8,9 @@ from sqlalchemy import func, select
 
 from app.config import settings
 from app.database import async_session, engine
-from app.models import Base, Program, Show, StationConfig, HistoryEntry, TeamMember, CommunityHighlight
+from app.models import Base, Show, StationConfig, HistoryEntry, TeamMember, CommunityHighlight
 from app.user_models import User
-from app.api import programs, events, tiers, auth, station_config, history, team, community, shows, upload
+from app.api import events, tiers, auth, station_config, history, team, community, shows, upload
 
 
 async def _ensure_station_config(session):
@@ -92,7 +92,6 @@ app.add_middleware(
 
 # Register routers
 app.include_router(auth.router, prefix="/api/auth", tags=["auth"])
-app.include_router(programs.router, prefix="/api/programs", tags=["programs"])
 app.include_router(events.router, prefix="/api/events", tags=["events"])
 app.include_router(tiers.router, prefix="/api/tiers", tags=["tiers"])
 app.include_router(station_config.router, prefix="/api/station-config", tags=["station-config"])