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>

app/routers/auth.py

@@ -32,17 +32,20 @@ async def login_submit(
 ):
     email = email.strip().lower()
 
-    # Check email is admin or invited
+    # Check email is admin, already registered, or has a pending invitation
     if email != ADMIN_EMAIL:
-        async with db.execute(
-            "SELECT id FROM invitations WHERE email = ?", (email,)
-        ) as cursor:
-            invitation = await cursor.fetchone()
-        if invitation is None:
-            return templates.TemplateResponse(
-                "auth/login.html",
-                {"request": request, "error": "This email address has not been invited."},
-            )
+        async with db.execute("SELECT id FROM users WHERE email = ?", (email,)) as cursor:
+            existing_user = await cursor.fetchone()
+        if existing_user is None:
+            async with db.execute(
+                "SELECT id FROM invitations WHERE email = ?", (email,)
+            ) as cursor:
+                invitation = await cursor.fetchone()
+            if invitation is None:
+                return templates.TemplateResponse(
+                    "auth/login.html",
+                    {"request": request, "error": "This email address has not been invited."},
+                )
 
     await create_magic_token(email, db)