ci: add Gitea Actions workflow with gofmt and test jobs

Add CI workflow at .gitea/workflows/ci.yml triggered on pull_request
with two jobs: fmt (gofmt check) and test (go test ./...).

Fix gofmt issues (import ordering) in 7 files so CI passes from
the start.

Fixes #7

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/ai_client/client_test.go

@@ -130,9 +130,9 @@ func TestDispatch_UsesCallbackBaseURL(t *testing.T) {
 	defer mockServer.Close()
 
 	cfg := &config.Config{
-		OpenClawURL:      mockServer.URL,
-		ListenAddr:       ":9999",
-		CallbackBaseURL:  "https://bridge.example.com/",
+		OpenClawURL:     mockServer.URL,
+		ListenAddr:      ":9999",
+		CallbackBaseURL: "https://bridge.example.com/",
 	}
 
 	task := &database.Task{