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/gorm/reader.go

@@ -246,7 +246,7 @@ func (r *Reader) getReceiverType(expr ast.Expr) string {
 }
 
 // parseTableNameMethod parses a TableName() method and extracts the table and schema name
-func (r *Reader) parseTableNameMethod(funcDecl *ast.FuncDecl) (tableName string, schemaName string) {
+func (r *Reader) parseTableNameMethod(funcDecl *ast.FuncDecl) (tableName, schemaName string) {
 	if funcDecl.Body == nil {
 		return "", ""
 	}
@@ -669,7 +669,7 @@ func (r *Reader) parseIndexesFromTag(table *models.Table, column *models.Column,
 }
 
 // extractTableFromGormTag extracts table and schema from gorm tag
-func (r *Reader) extractTableFromGormTag(tag string) (tablename string, schemaName string) {
+func (r *Reader) extractTableFromGormTag(tag string) (tablename, schemaName string) {
 	// This is typically set via TableName() method, not in tags
 	// We'll return empty strings and rely on deriveTableName
 	return "", ""
@@ -794,12 +794,12 @@ func (r *Reader) parseTypeWithLength(typeStr string) (baseType string, length in
 		if pgsql.SupportsLength(rawBaseType) && !strings.Contains(parens, ",") {
 			if _, err := fmt.Sscanf(parens, "%d", &length); err == nil {
 				baseType = pgsql.CanonicalizeBaseType(rawBaseType)
-				return
+				return baseType, length
 			}
 		}
 	}
 
-	return
+	return baseType, length
 }
 
 // parseTypeWithReferences parses a type string and extracts base type, length, and references
@@ -816,12 +816,12 @@ func (r *Reader) parseTypeWithReferences(typeStr string) (baseType string, lengt
 
 		// Parse base type for length
 		baseType, length = r.parseTypeWithLength(baseTypePart)
-		return
+		return baseType, length, refInfo
 	}
 
 	// No references, just parse type and length
 	baseType, length = r.parseTypeWithLength(typeStr)
-	return
+	return baseType, length, refInfo
 }
 
 // parseGormTag parses a gorm tag string into a map