chore: remove college basketball (CBB) from iOS app

Remove CBB (~5,000+ games per season) to reduce complexity.

Changes:
- Remove .cbb enum case from Sport
- Remove CBB theme color (cbbMint)
- Update documentation to reflect 7 supported leagues

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -4,7 +4,7 @@ An iOS app for planning multi-stop sports road trips across North America. Plan
 
 ## Features
 
-- **Multi-Sport Trip Planning** - Plan trips across 8 professional and college leagues
+- **Multi-Sport Trip Planning** - Plan trips across 7 professional leagues
 - **Three Planning Modes**
   - **By Date Range** - Find the best games within your travel window
   - **By Must-See Games** - Build a trip around specific matchups you want to attend
@@ -26,7 +26,6 @@ An iOS app for planning multi-stop sports road trips across North America. Plan
 | MLS | Soccer | February - December |
 | WNBA | Basketball | May - October |
 | NWSL | Soccer | March - November |
-| CBB | College Basketball | November - April |
 
 ## Requirements