chore(ci): add govulncheck, staticcheck, go vet, gofumpt gates

* Add lint/format checks to the Gitea release workflow and Makefile
  (targets: vet, fmt, fmt-check, staticcheck, govulncheck, check)
* Switch .golangci.json formatter from gofmt to gofumpt (extra.group-params)
* Bump golang.org/x/text 0.37.0 -> 0.39.0 for GO-2026-5970; re-vendor
* Fix staticcheck S1011 in pkg/diff; drop unused pgsql writer helpers
* Fix gocritic unnamedResult (pkg/diff) and rangeValCopy (pkg/pgsql)
* Apply gofumpt + goimports formatting across the tree

cmd/relspec/inspect.go

@@ -193,7 +193,7 @@ func runInspect(cmd *cobra.Command, args []string) error {
 
 	// Write output
 	if inspectOutputPath != "" {
-		err = os.WriteFile(inspectOutputPath, []byte(formattedReport), 0644)
+		err = os.WriteFile(inspectOutputPath, []byte(formattedReport), 0o644)
 		if err != nil {
 			return fmt.Errorf("failed to write output file: %w", err)
 		}