Upgrade Go version and add Air to Dockerfile

Add Air live‑reload tool and update the base image to golang:1.25.
Configure docker‑compose with code mounts and a cached Go module
volume, and switch the container command to run Air.

docker-compose.yaml

@@ -3,9 +3,14 @@ services:
     build:
       context: .
       dockerfile: Dockerfile
-
     ports:
       - "8080:8080"
     environment:
       - GO111MODULE=on
-    command: ["./tmp/main"]
+    volumes:
+      - .:/app # Mount your code
+      - /app/tmp # Exclude tmp (built binaries)
+      - go-mod-cache:/go/pkg/mod # Cache Go modules
+
+volumes:
+  go-mod-cache: