add example environment configuration and requirements file

.env.example

@@ -0,0 +1,13 @@
+# Copy this file to .env and fill in the values
+
+# openrouter.ai API key
+OPENROUTER_API_KEY=
+
+# JWT secret for signing tokens (generate with: python -c "import secrets; print(secrets.token_hex(32))")
+JWT_SECRET=
+
+# Path to DuckDB database file
+DB_PATH=data/app.db
+
+# Log level (DEBUG, INFO, WARNING, ERROR)
+LOG_LEVEL=INFO