feat(actions): add branch filters to run list (#37826)

## Summary

- Add a Branch filter dropdown to the repo Actions run list web UI
- Wire `?branch=` query param through the web handler, matching the
existing REST API filter behavior
- Source the Branch dropdown from the indexed `branch` table (filtering
out deleted branches) instead of scanning `action_run.ref`, addressing
review feedback about unindexed columns

The Event filter was dropped after review: a static list of supported
events was noisy as UX, and querying distinct values from
`action_run.trigger_event` is slow because the column is not indexed.
`FindRunOptions.TriggerEvent` is kept for the REST API.

Closes #25042

---------

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

tests/integration/actions_list_filter_test.go

@@ -0,0 +1,68 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package integration
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+	"testing"
+
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/tests"
+
+	"github.com/PuerkitoBio/goquery"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestActionsListFilters(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	user5 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 4})
+	session := loginUser(t, user5.Name)
+	actionsURL := fmt.Sprintf("/%s/%s/actions", user5.Name, repo.Name)
+
+	t.Run("BranchDropdownListsBranches", func(t *testing.T) {
+		req := NewRequest(t, "GET", actionsURL)
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+
+		var labels []string
+		htmlDoc.doc.Find(`[data-test-id="filter-branch"] .menu a.item`).Each(func(_ int, a *goquery.Selection) {
+			labels = append(labels, strings.TrimSpace(a.Text()))
+		})
+		assert.Contains(t, labels, "master")
+	})
+
+	t.Run("FilterByBranch", func(t *testing.T) {
+		req := NewRequest(t, "GET", actionsURL+"?branch=master")
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+
+		refs := htmlDoc.doc.Find(".run-list .run-list-ref")
+		assert.Positive(t, refs.Length(), "filtered run list should not be empty")
+		refs.Each(func(_ int, sel *goquery.Selection) {
+			assert.Equal(t, "master", strings.TrimSpace(sel.Text()))
+		})
+	})
+
+	t.Run("PaginationPreservesFilters", func(t *testing.T) {
+		req := NewRequest(t, "GET", actionsURL+"?branch=master&limit=1")
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+
+		pageLinks := htmlDoc.doc.Find(".pagination a[href]")
+		assert.Positive(t, pageLinks.Length(), "pagination should be rendered")
+		pageLinks.Each(func(_ int, a *goquery.Selection) {
+			u, err := url.Parse(a.AttrOr("href", ""))
+			require.NoError(t, err)
+			assert.Equal(t, "master", u.Query().Get("branch"), "pagination link must preserve branch filter")
+		})
+	})
+}