Remove dead code identified by deadcode tool (#37271)

Ran [`deadcode`](https://pkg.go.dev/golang.org/x/tools/cmd/deadcode)
(`-test ./...`) to find functions, methods and error types unreachable
from any call path (including tests), and removed the truly-dead ones.

Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>

models/actions/run_list.go

@@ -7,7 +7,6 @@ import (
 	"context"
 
 	"code.gitea.io/gitea/models/db"
-	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/container"
 	"code.gitea.io/gitea/modules/translation"
@@ -25,12 +24,6 @@ func (runs RunList) GetUserIDs() []int64 {
 	})
 }
 
-func (runs RunList) GetRepoIDs() []int64 {
-	return container.FilterSlice(runs, func(run *ActionRun) (int64, bool) {
-		return run.RepoID, true
-	})
-}
-
 func (runs RunList) LoadTriggerUser(ctx context.Context) error {
 	userIDs := runs.GetUserIDs()
 	users := make(map[int64]*user_model.User, len(userIDs))
@@ -50,18 +43,6 @@ func (runs RunList) LoadTriggerUser(ctx context.Context) error {
 	return nil
 }
 
-func (runs RunList) LoadRepos(ctx context.Context) error {
-	repoIDs := runs.GetRepoIDs()
-	repos, err := repo_model.GetRepositoriesMapByIDs(ctx, repoIDs)
-	if err != nil {
-		return err
-	}
-	for _, run := range runs {
-		run.Repo = repos[run.RepoID]
-	}
-	return nil
-}
-
 type FindRunOptions struct {
 	db.ListOptions
 	RepoID           int64