Add priority to protected branch (#32286)

## Solves

Currently for rules to re-order them you have to alter the creation
date. so you basicly have to delete and recreate them in the right
order. This is more than just inconvinient ...

## Solution

Add a new col for prioritization

## Demo WebUI Video

https://github.com/user-attachments/assets/92182a31-9705-4ac5-b6e3-9bb74108cbd1


---
*Sponsored by Kithara Software GmbH*

models/git/protected_branch_test.go

@@ -7,6 +7,10 @@ import (
 	"fmt"
 	"testing"
 
+	"code.gitea.io/gitea/models/db"
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+
 	"github.com/stretchr/testify/assert"
 )
 
@@ -76,3 +80,77 @@ func TestBranchRuleMatch(t *testing.T) {
 		)
 	}
 }
+
+func TestUpdateProtectBranchPriorities(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
+
+	// Create some test protected branches with initial priorities
+	protectedBranches := []*ProtectedBranch{
+		{
+			RepoID:   repo.ID,
+			RuleName: "master",
+			Priority: 1,
+		},
+		{
+			RepoID:   repo.ID,
+			RuleName: "develop",
+			Priority: 2,
+		},
+		{
+			RepoID:   repo.ID,
+			RuleName: "feature/*",
+			Priority: 3,
+		},
+	}
+
+	for _, pb := range protectedBranches {
+		_, err := db.GetEngine(db.DefaultContext).Insert(pb)
+		assert.NoError(t, err)
+	}
+
+	// Test updating priorities
+	newPriorities := []int64{protectedBranches[2].ID, protectedBranches[0].ID, protectedBranches[1].ID}
+	err := UpdateProtectBranchPriorities(db.DefaultContext, repo, newPriorities)
+	assert.NoError(t, err)
+
+	// Verify new priorities
+	pbs, err := FindRepoProtectedBranchRules(db.DefaultContext, repo.ID)
+	assert.NoError(t, err)
+
+	expectedPriorities := map[string]int64{
+		"feature/*": 1,
+		"master":    2,
+		"develop":   3,
+	}
+
+	for _, pb := range pbs {
+		assert.Equal(t, expectedPriorities[pb.RuleName], pb.Priority)
+	}
+}
+
+func TestNewProtectBranchPriority(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
+
+	err := UpdateProtectBranch(db.DefaultContext, repo, &ProtectedBranch{
+		RepoID:   repo.ID,
+		RuleName: "branch-1",
+		Priority: 1,
+	}, WhitelistOptions{})
+	assert.NoError(t, err)
+
+	newPB := &ProtectedBranch{
+		RepoID:   repo.ID,
+		RuleName: "branch-2",
+		// Priority intentionally omitted
+	}
+
+	err = UpdateProtectBranch(db.DefaultContext, repo, newPB, WhitelistOptions{})
+	assert.NoError(t, err)
+
+	savedPB2, err := GetFirstMatchProtectedBranchRule(db.DefaultContext, repo.ID, "branch-2")
+	assert.NoError(t, err)
+	assert.Equal(t, int64(2), savedPB2.Priority)
+}