**feat(compose):** add separate deploy and dev Docker Compose files

- Introduced `compose.yml` for deployment, pulling the image from the registry
- Added `compose.dev.yml` for local development, building the image from source
- Updated `README.md` and `.claude/CLAUDE.md` with instructions for both configurations
- Introduced `DB_PATH` environment variable to customize SQLite database file location
- Updated `main.go` to use `DB_PATH` with a default fallback (`./diun.db`)

cmd/diunwebhook/main.go

@@ -14,7 +14,11 @@ import (
 )
 
 func main() {
-	if err := diun.InitDB("./diun.db"); err != nil {
+	dbPath := os.Getenv("DB_PATH")
+	if dbPath == "" {
+		dbPath = "./diun.db"
+	}
+	if err := diun.InitDB(dbPath); err != nil {
 		log.Fatalf("InitDB: %v", err)
 	}