Add OBS widgets for streamers

- Add widget token authentication system
- Create leaderboard, current assignment, and progress widgets
- Support dark, light, and neon themes
- Add widget settings modal for URL generation
- Fix avatar loading through backend API proxy

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/app/schemas/__init__.py

@@ -134,6 +134,15 @@ from app.schemas.promo_code import (
     PromoCodeRedemptionUser,
 )
 from app.schemas.user import ShopItemPublic
+from app.schemas.widget import (
+    WidgetTokenCreate,
+    WidgetTokenResponse,
+    WidgetTokenListItem,
+    WidgetLeaderboardEntry,
+    WidgetLeaderboardResponse,
+    WidgetCurrentResponse,
+    WidgetProgressResponse,
+)
 
 __all__ = [
     # User
@@ -260,4 +269,12 @@ __all__ = [
     "PromoCodeRedeemResponse",
     "PromoCodeRedemptionResponse",
     "PromoCodeRedemptionUser",
+    # Widget
+    "WidgetTokenCreate",
+    "WidgetTokenResponse",
+    "WidgetTokenListItem",
+    "WidgetLeaderboardEntry",
+    "WidgetLeaderboardResponse",
+    "WidgetCurrentResponse",
+    "WidgetProgressResponse",
 ]