docs: consolidate documentation into organized structure

- Move 12 markdown files from root to docs/ subdirectories
- Organize documentation by category:
  • docs/troubleshooting/ (1 file)  - Technical troubleshooting guides
  • docs/deployment/      (4 files) - Deployment and security documentation
  • docs/guides/          (3 files) - Feature-specific guides
  • docs/planning/        (4 files) - Planning and improvement proposals

Root directory cleanup:
- Reduced from 16 to 4 markdown files in root
- Only essential project files remain:
  • CLAUDE.md (AI instructions)
  • README.md (Main project readme)
  • CLEANUP_PLAN.md (Current cleanup plan)
  • SRC_STRUCTURE_IMPROVEMENTS.md (Structure improvements)

This improves:
✅ Documentation discoverability
✅ Logical organization by purpose
✅ Clean root directory
✅ Better maintainability

src/Framework/Config/EnvKey.php

@@ -12,6 +12,7 @@ enum EnvKey: string
     case APP_KEY = 'APP_KEY';
     case APP_TIMEZONE = 'APP_TIMEZONE';
     case APP_LOCALE = 'APP_LOCALE';
+    case APP_URL = 'APP_URL';
 
     // Feature Flags
     case ENABLE_CONTEXT_AWARE_INITIALIZERS = 'ENABLE_CONTEXT_AWARE_INITIALIZERS';
@@ -31,6 +32,18 @@ enum EnvKey: string
     case RAPIDMAIL_PASSWORD = 'RAPIDMAIL_PASSWORD';
     case RAPIDMAIL_TEST_MODE = 'RAPIDMAIL_TEST_MODE';
 
+    // OAuth - Spotify
+    case SPOTIFY_CLIENT_ID = 'SPOTIFY_CLIENT_ID';
+    case SPOTIFY_CLIENT_SECRET = 'SPOTIFY_CLIENT_SECRET';
+    case SPOTIFY_REDIRECT_URI = 'SPOTIFY_REDIRECT_URI';
+
+    // OAuth - Apple Music
+    case APPLE_MUSIC_CLIENT_ID = 'APPLE_MUSIC_CLIENT_ID';
+    case APPLE_MUSIC_TEAM_ID = 'APPLE_MUSIC_TEAM_ID';
+    case APPLE_MUSIC_KEY_ID = 'APPLE_MUSIC_KEY_ID';
+    case APPLE_MUSIC_PRIVATE_KEY = 'APPLE_MUSIC_PRIVATE_KEY';
+    case APPLE_MUSIC_REDIRECT_URI = 'APPLE_MUSIC_REDIRECT_URI';
+
     // ETag Configuration
     case ETAG_ENABLED = 'ETAG_ENABLED';
     case ETAG_PREFER_WEAK = 'ETAG_PREFER_WEAK';
@@ -42,4 +55,7 @@ enum EnvKey: string
     case REDIS_PORT = 'REDIS_PORT';
     case REDIS_PASSWORD = 'REDIS_PASSWORD';
 
+    // Vault Configuration
+    case VAULT_ENCRYPTION_KEY = 'VAULT_ENCRYPTION_KEY';
+
 }