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>

.env.example

@@ -13,6 +13,10 @@ ENV=development
 # Path to the SQLite database file (inside the container)
 DATABASE_PATH=/data/skinspins.db
 
+# GolfCourseAPI key — get one at https://www.golfcourseapi.com
+# Leave empty to disable the course search/import feature
+GOLF_COURSE_API_KEY=
+
 # SMTP email settings (leave SMTP_HOST empty to disable email and log links instead)
 SMTP_HOST=smtp.example.com
 SMTP_PORT=587