Add Skins format, GolfCourseAPI import, and UX improvements

- Add Skins game format with optional carryover, mirroring BBB scoring pattern
- Add GolfCourseAPI integration for course search and import (httpx)
- Unwrap {"course": {}} API response envelope on import
- Add searchable course combobox and player filter to new game form
- Redirect to summary page after finishing a game
- Fix auth to allow registered users without a pending invitation
- Fix hardcoded BBB format in create_game; store carryover flag in DB
- Add game summary/scorecard view for completed games
- Add live games social stream to dashboard
- Add course name + subtitle to recent game cards
- Reorder nav: Home → Games → Admin → Profile

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

requirements.txt

@@ -6,3 +6,4 @@ python-multipart==0.0.12
 python-dotenv==1.0.1
 itsdangerous==2.2.0
 aiosmtplib==3.0.1
+httpx==0.28.1