Added example .env file.

.env.example

@@ -0,0 +1,17 @@
+# DosVault Environment Configuration
+# Copy this file to .env and fill in your values
+
+# IGDB API Credentials (required)
+# Get these from https://dev.twitch.tv/console/apps
+IGDB_CLIENT_ID=your_twitch_client_id_here
+IGDB_SECRET_KEY=your_twitch_client_secret_here
+
+# ROM Directory Path
+# Path to your ROM collection (will be mounted read-only in container)
+ROMS_PATH=/path/to/your/roms
+
+# Application Settings (optional - can be configured via web interface)
+# These are automatically derived from DOSFRONTEND_CONFIG_DIR in Docker
+# DOSVAULT_HOST=localhost  
+# DOSVAULT_PORT=8080
+# DOSVAULT_WEBSOCKET_PORT=8081