feat: delay show rotation during live recording window

Decouple the like-window boundary (Wed 10pm ET) from when the system
rotates to a new show. NTR_SHOW_ROTATION_DELAY_HOURS=2 keeps the
previous week's show visible during the ~2 hour recording, then creates
the new show at midnight.

Made-with: Cursor

src/ntr_fetcher/config.py

@@ -12,6 +12,7 @@ class Settings(BaseSettings):
     soundcloud_user: str = "nicktherat"
     show_day: int = 2
     show_hour: int = 22
+    show_rotation_delay_hours: int = 0
 
     web_user: str | None = None
     web_password: str | None = None