release: bump version to 1.4(p) (versionCode 14)

- Update versionCode 12 → 14, versionName 1.3(p) → 1.4(p)
- Update pubspec.yaml version to 1.4.0+14
- Add CHANGELOG.md with full version history
- Update README.md: version badge + changelog section
- Desktop Contribute Dashboard rebuilt to match web version
  - Contributor Dashboard title, 3-tab nav (Contribute/Leaderboard/Achievements)
  - Two-column submit form, tier milestone progress bar
  - Desktop leaderboard with podium, filters, rank table (green points)
  - Desktop achievements 3-column badge grid
  - Inline Reward Shop with RP balance
- Gamification feature module (EP, RP, leaderboard, achievements, shop)
- Profile screen redesigned to match web app layout with animations
- Home screen bottom sheet date filter chips
- Updated API endpoints, login/event detail screens, theme colors
- Added Gilroy font suite, responsive layout improvements

lib/core/api/api_endpoints.dart

@@ -23,4 +23,12 @@ class ApiEndpoints {
   // static const String bookEvent = "$baseUrl/events/book-event/";
   // static const String userSuccessBookings = "$baseUrl/events/event/user-success-bookings/";
   // static const String userCancelledBookings = "$baseUrl/events/event/user-cancelled-bookings/";
+
+  // Gamification / Contributor Module (TechDocs v2)
+  static const String gamificationProfile = "$baseUrl/v1/user/gamification-profile/";
+  static const String leaderboard         = "$baseUrl/v1/leaderboard/";
+  static const String shopItems           = "$baseUrl/v1/shop/items/";
+  static const String shopRedeem          = "$baseUrl/v1/shop/redeem/";
+  static const String contributeSubmit    = "$baseUrl/v1/contributions/submit/";
+  static const String gradeContribution   = "$baseUrl/v1/admin/contributions/"; // append {id}/grade/
 }