Add user badges (#36752)

Implemented #29798

This feature implements list badges, create new badges, view badge, edit
badge and assign badge to users.

- List all badges
![(screenshot)](https://github.com/user-attachments/assets/9dbf243e-c704-49f8-915a-73704e226da9)
- Create new badges
![(screenshot)](https://github.com/user-attachments/assets/8a3fff7e-fe6f-49b0-a7c5-bbba34478019)
- View badge
![(screenshot)](https://github.com/user-attachments/assets/dd7a882b-6e2c-47d2-93e0-05a2698a41e5)
![(screenshot)](https://private-user-images.githubusercontent.com/75789103/558982759-53536300-e189-406b-8b0e-824e1a768b92.png?jwt=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.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.4aAfpFaziiXDG7W2HaNJop0B62-NR4f0Ni9YNjTZq0M)
- Edit badge
![(screenshot)](https://github.com/user-attachments/assets/7124671a-ed97-4c98-ac7d-34863377fa62)
- Add user to badge
![(screenshot)](https://github.com/user-attachments/assets/3438b492-0197-4acb-b9f2-2f9f7c80582e)

models/migrations/v1_26/v329.go

@@ -0,0 +1,62 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_26
+
+import (
+	"fmt"
+
+	"xorm.io/xorm"
+	"xorm.io/xorm/schemas"
+)
+
+type UserBadge struct { //revive:disable-line:exported
+	ID      int64 `xorm:"pk autoincr"`
+	BadgeID int64
+	UserID  int64
+}
+
+// TableIndices implements xorm's TableIndices interface
+func (n *UserBadge) TableIndices() []*schemas.Index {
+	indices := make([]*schemas.Index, 0, 1)
+	ubUnique := schemas.NewIndex("unique_user_badge", schemas.UniqueType)
+	ubUnique.AddColumn("user_id", "badge_id")
+	indices = append(indices, ubUnique)
+	return indices
+}
+
+// AddUniqueIndexForUserBadge adds a compound unique indexes for user badge table
+// and it replaces an old index on user_id
+func AddUniqueIndexForUserBadge(x *xorm.Engine) error {
+	// remove possible duplicated records in table user_badge
+	type result struct {
+		UserID  int64
+		BadgeID int64
+		Cnt     int
+	}
+	var results []result
+	if err := x.Select("user_id, badge_id, count(*) as cnt").
+		Table("user_badge").
+		GroupBy("user_id, badge_id").
+		Having("count(*) > 1").
+		Find(&results); err != nil {
+		return err
+	}
+	for _, r := range results {
+		if x.Dialect().URI().DBType == schemas.MSSQL {
+			if _, err := x.Exec(fmt.Sprintf("delete from user_badge where id in (SELECT top %d id FROM user_badge WHERE user_id = ? and badge_id = ?)", r.Cnt-1), r.UserID, r.BadgeID); err != nil {
+				return err
+			}
+		} else {
+			var ids []int64
+			if err := x.SQL("SELECT id FROM user_badge WHERE user_id = ? and badge_id = ? limit ?", r.UserID, r.BadgeID, r.Cnt-1).Find(&ids); err != nil {
+				return err
+			}
+			if _, err := x.Table("user_badge").In("id", ids).Delete(); err != nil {
+				return err
+			}
+		}
+	}
+
+	return x.Sync(new(UserBadge))
+}

models/migrations/v1_26/v329_test.go

@@ -0,0 +1,85 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_26
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models/migrations/base"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type UserBadgeBefore struct {
+	ID      int64 `xorm:"pk autoincr"`
+	BadgeID int64
+	UserID  int64 `xorm:"INDEX"`
+}
+
+func (UserBadgeBefore) TableName() string {
+	return "user_badge"
+}
+
+func Test_AddUniqueIndexForUserBadge(t *testing.T) {
+	x, deferable := base.PrepareTestEnv(t, 0, new(UserBadgeBefore))
+	defer deferable()
+	if x == nil || t.Failed() {
+		return
+	}
+
+	testData := []*UserBadgeBefore{
+		{UserID: 1, BadgeID: 1},
+		{UserID: 1, BadgeID: 1}, // duplicate
+		{UserID: 2, BadgeID: 1},
+		{UserID: 1, BadgeID: 2},
+		{UserID: 3, BadgeID: 3},
+		{UserID: 3, BadgeID: 3}, // duplicate
+	}
+
+	for _, data := range testData {
+		_, err := x.Insert(data)
+		assert.NoError(t, err)
+	}
+
+	// check that we have duplicates
+	count, err := x.Where("user_id = ? AND badge_id = ?", 1, 1).Count(&UserBadgeBefore{})
+	assert.NoError(t, err)
+	assert.Equal(t, int64(2), count)
+
+	count, err = x.Where("user_id = ? AND badge_id = ?", 3, 3).Count(&UserBadgeBefore{})
+	assert.NoError(t, err)
+	assert.Equal(t, int64(2), count)
+
+	totalCount, err := x.Count(&UserBadgeBefore{})
+	assert.NoError(t, err)
+	assert.Equal(t, int64(6), totalCount)
+
+	// run the migration
+	if err := AddUniqueIndexForUserBadge(x); err != nil {
+		assert.NoError(t, err)
+		return
+	}
+
+	// verify the duplicates were removed
+	count, err = x.Where("user_id = ? AND badge_id = ?", 1, 1).Count(&UserBadgeBefore{})
+	assert.NoError(t, err)
+	assert.Equal(t, int64(1), count)
+
+	count, err = x.Where("user_id = ? AND badge_id = ?", 3, 3).Count(&UserBadgeBefore{})
+	assert.NoError(t, err)
+	assert.Equal(t, int64(1), count)
+
+	// check total count
+	totalCount, err = x.Count(&UserBadgeBefore{})
+	assert.NoError(t, err)
+	assert.Equal(t, int64(4), totalCount)
+
+	// fail to insert a duplicate
+	_, err = x.Insert(&UserBadge{UserID: 1, BadgeID: 1})
+	assert.Error(t, err)
+
+	// succeed adding a non-duplicate
+	_, err = x.Insert(&UserBadge{UserID: 4, BadgeID: 1})
+	assert.NoError(t, err)
+}