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The Programs feature is superseded by Shows, which provides a more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/models.py

@@ -17,18 +17,6 @@ class Base(DeclarativeBase):
     pass
 
 
-class Program(Base):
-    __tablename__ = "programs"
-
-    id = Column(Integer, primary_key=True, autoincrement=True)
-    day_of_week = Column(Integer, nullable=False)       # 1=Mon … 7=Sun
-    day_label = Column(String(10), nullable=False)      # "Monday", …
-    time = Column(String(10), nullable=False)           # "6:00 AM"
-    title = Column(String(200), nullable=False)
-    host = Column(String(100), nullable=False)
-    genre = Column(String(80), nullable=False)
-
-
 class Show(Base):
     __tablename__ = "shows"