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/sqltypes/sql_types.go

@@ -111,6 +111,7 @@ func (n *SqlNull[T]) Scan(value any) error {
 		return n.FromString(fmt.Sprintf("%v", value))
 	}
 }
+
 func (n *SqlNull[T]) FromString(s string) error {
 	s = strings.TrimSpace(s)
 	n.Valid = false
@@ -448,7 +449,7 @@ type (
 type SqlTimeStamp struct{ SqlNull[time.Time] }
 
 func (t SqlTimeStamp) MarshalJSON() ([]byte, error) {
-	if !t.Valid || t.Val.IsZero() || t.Val.Before(time.Date(0002, 1, 1, 0, 0, 0, 0, time.UTC)) {
+	if !t.Valid || t.Val.IsZero() || t.Val.Before(time.Date(0o002, 1, 1, 0, 0, 0, 0, time.UTC)) {
 		return []byte("null"), nil
 	}
 	return fmt.Appendf(nil, `"%s"`, t.Val.Format("2006-01-02T15:04:05")), nil
@@ -465,14 +466,14 @@ func (t *SqlTimeStamp) UnmarshalJSON(b []byte) error {
 }
 
 func (t SqlTimeStamp) Value() (driver.Value, error) {
-	if !t.Valid || t.Val.IsZero() || t.Val.Before(time.Date(0002, 1, 1, 0, 0, 0, 0, time.UTC)) {
+	if !t.Valid || t.Val.IsZero() || t.Val.Before(time.Date(0o002, 1, 1, 0, 0, 0, 0, time.UTC)) {
 		return nil, nil
 	}
 	return t.Val.Format("2006-01-02T15:04:05"), nil
 }
 
 func (t SqlTimeStamp) MarshalYAML() (any, error) {
-	if !t.Valid || t.Val.IsZero() || t.Val.Before(time.Date(0002, 1, 1, 0, 0, 0, 0, time.UTC)) {
+	if !t.Valid || t.Val.IsZero() || t.Val.Before(time.Date(0o002, 1, 1, 0, 0, 0, 0, time.UTC)) {
 		return nil, nil
 	}
 	return t.Val.Format("2006-01-02T15:04:05"), nil
@@ -489,7 +490,7 @@ func (t *SqlTimeStamp) UnmarshalYAML(value *yaml.Node) error {
 }
 
 func (t SqlTimeStamp) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
-	if !t.Valid || t.Val.IsZero() || t.Val.Before(time.Date(0002, 1, 1, 0, 0, 0, 0, time.UTC)) {
+	if !t.Valid || t.Val.IsZero() || t.Val.Before(time.Date(0o002, 1, 1, 0, 0, 0, 0, time.UTC)) {
 		return e.EncodeElement("", start)
 	}
 	return e.EncodeElement(t.Val.Format("2006-01-02T15:04:05"), start)

pkg/sqltypes/sql_types_test.go

@@ -955,4 +955,3 @@ func TestSqlByteArray_Base64_RoundTrip(t *testing.T) {
 		t.Errorf("Round-trip failed: expected %v, got %v", original, b3.Val)
 	}
 }
-