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/readers/dbml/reader_test.go

@@ -689,7 +689,7 @@ func TestReadDirectory_CommentedRefsLast(t *testing.T) {
 func TestReadDirectory_EmptyDirectory(t *testing.T) {
 	// Create a temporary empty directory
 	tmpDir := filepath.Join("..", "..", "..", "tests", "assets", "dbml", "empty_test_dir")
-	err := os.MkdirAll(tmpDir, 0755)
+	err := os.MkdirAll(tmpDir, 0o755)
 	if err != nil {
 		t.Fatalf("Failed to create temp directory: %v", err)
 	}
@@ -956,7 +956,7 @@ func TestReader_CompositePKIndex(t *testing.T) {
 `
 	dir := t.TempDir()
 	path := filepath.Join(dir, "composite_pk.dbml")
-	if err := os.WriteFile(path, []byte(dbmlContent), 0644); err != nil {
+	if err := os.WriteFile(path, []byte(dbmlContent), 0o644); err != nil {
 		t.Fatalf("failed to write fixture: %v", err)
 	}
 
@@ -1005,7 +1005,7 @@ func TestReader_ColumnPKOrderPreserved(t *testing.T) {
 `
 	dir := t.TempDir()
 	path := filepath.Join(dir, "column_pk_order.dbml")
-	if err := os.WriteFile(path, []byte(dbmlContent), 0644); err != nil {
+	if err := os.WriteFile(path, []byte(dbmlContent), 0o644); err != nil {
 		t.Fatalf("failed to write fixture: %v", err)
 	}