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

pkg/inspector/report.go

@@ -141,7 +141,7 @@ func (f *MarkdownFormatter) formatHeader(text string) string {
 	return f.formatBold("# " + text)
 }
 
-func (f *MarkdownFormatter) formatSubheader(text string, color string) string {
+func (f *MarkdownFormatter) formatSubheader(text, color string) string {
 	header := "### " + text
 	if f.UseColors {
 		return color + colorBold + header + colorReset
@@ -156,7 +156,7 @@ func (f *MarkdownFormatter) formatBold(text string) string {
 	return "**" + text + "**"
 }
 
-func (f *MarkdownFormatter) colorize(text string, color string) string {
+func (f *MarkdownFormatter) colorize(text, color string) string {
 	if f.UseColors {
 		return color + text + colorReset
 	}