fix(os/gstructs): strip tag options in TagPriorityName to avoid field name pollution (#4681)

## Summary
- Fix `TagPriorityName()` to strip comma-separated tag options (e.g.,
`omitempty`) from tag values
- Before: `json:"user_name,omitempty"` → field name =
`user_name,omitempty`
- After: `json:"user_name,omitempty"` → field name = `user_name`
- Aligns with `structcache.genPriorityTagAndFieldName()` which already
handles this correctly
- When tag name is empty (e.g., `gconv:",omitempty"`), continues to next
priority tag instead of breaking

## Test plan
- [x] Reproduced bug: `RuleFuncInput.Field` was `user_name,omitempty`
instead of `user_name`
- [x] Verified fix: field name correctly extracted as `user_name`
- [x] Verified fallthrough: `gconv:",omitempty"` + `json:"name"` → uses
`name`
- [x] Existing `Test_Fields_TagPriorityName` passes
- [x] Full `os/gstructs` test suite passes
- [x] Full `util/gvalid` test suite passes
- [x] Full `util/gconv` test suite passes

closes #4665

os/gstructs/gstructs_field_tag.go

@@ -101,8 +101,12 @@ func (f *Field) TagPriorityName() string {
 	name := f.Name()
 	for _, tagName := range gtag.StructTagPriority {
 		if tagValue := f.Tag(tagName); tagValue != "" {
-			name = tagValue
-			break
+			// Strip tag options after comma, e.g., json:"name,omitempty" -> "name".
+			tagValue = strings.Split(tagValue, ",")[0]
+			if tagValue != "" {
+				name = tagValue
+				break
+			}
 		}
 	}
 	return name

os/gstructs/gstructs_z_unit_test.go

@@ -546,4 +546,32 @@ func Test_Fields_TagPriorityName(t *testing.T) {
 		t.Assert(fields[2].TagPriorityName(), "pass_json")
 		t.Assert(fields[3].TagPriorityName(), "IsMen")
 	})
+	// Tag with omitempty option should return name only, not "name,omitempty".
+	gtest.C(t, func(t *gtest.T) {
+		type User struct {
+			Name string `json:"user_name,omitempty"`
+			Age  uint   `gconv:"age,string" json:"age_json"`
+		}
+		var user *User
+		fields, _ := gstructs.Fields(gstructs.FieldsInput{
+			Pointer:         user,
+			RecursiveOption: 0,
+		})
+		t.Assert(fields[0].TagPriorityName(), "user_name")
+		t.Assert(fields[1].TagPriorityName(), "age")
+	})
+	// Empty tag name with options (e.g., gconv:",omitempty") should fallthrough to next priority tag.
+	gtest.C(t, func(t *gtest.T) {
+		type User struct {
+			Name string `gconv:",omitempty" json:"name_json"`
+			Age  uint   `gconv:",string" param:",omitempty" json:"age_json"`
+		}
+		var user *User
+		fields, _ := gstructs.Fields(gstructs.FieldsInput{
+			Pointer:         user,
+			RecursiveOption: 0,
+		})
+		t.Assert(fields[0].TagPriorityName(), "name_json")
+		t.Assert(fields[1].TagPriorityName(), "age_json")
+	})
 }