fix(env): Sync .env.example with actual .env variables

- Added LIBRARIES_ROOT_PATH to .env.example (was commented out)
- Removed ADMIN_UI_LISTEN_ADDR (admin-ui no longer exists)
- Improved documentation for LIBRARIES_ROOT_PATH variable

Note: .env changes (removed ADMIN_UI_LISTEN_ADDR) are local only
due to .gitignore - users should update their .env manually.

.env.example

@@ -41,8 +41,10 @@ DATABASE_URL=postgres://stripstream:stripstream@postgres:5432/stripstream
 MEILI_URL=http://meilisearch:7700
 
 # =============================================================================
-# Optional - Development only
+# Storage Configuration
 # =============================================================================
 
-# Path to libraries directory (default: /libraries in Docker)
-# LIBRARIES_ROOT_PATH=/libraries
+# Path to libraries directory
+# In Docker: leave as default /libraries
+# For local dev: set to your local libraries folder path
+LIBRARIES_ROOT_PATH=/libraries