refactor(actions): small cleanups across models, services and routers (#39722)

Collection of small, behaviour-preserving cleanups in the Actions code.

- Fix log and error prefixes that named non-existent or wrong functions,
and wrap errors with `%w` so `errors.Is` keeps working.
- Remove unused code.
- Rely on `ctx.ServerError` / `ctx.APIErrorAuto`, which already map
`util.ErrNotExist` and friends, instead of equivalent hand-written
switches.
- Load runs referenced by commit statuses with one query instead of one
per run (used on every PR view); the result order is now stable.
- Encode an event's payload once instead of up to three times.
- Share the duplicated runner-token "get or create" logic and the
"notify and emit" call pair.
- Simplify `ToActionArtifact` / `ToActionRunner` signatures.

---------

Signed-off-by: bircni <bircni@icloud.com>
Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

services/convert/convert.go

@@ -720,7 +720,7 @@ func ResolveActionWorkflowForRun(ctx context.Context, repo *repo_model.Repositor
 }
 
 // ToActionArtifact convert a actions_model.ActionArtifact to an api.ActionArtifact
-func ToActionArtifact(repo *repo_model.Repository, art *actions_model.ActionArtifact) (*api.ActionArtifact, error) {
+func ToActionArtifact(repo *repo_model.Repository, art *actions_model.ActionArtifact) *api.ActionArtifact {
 	url := fmt.Sprintf("%s/actions/artifacts/%d", repo.APIURL(), art.ID)
 
 	return &api.ActionArtifact{
@@ -738,10 +738,10 @@ func ToActionArtifact(repo *repo_model.Repository, art *actions_model.ActionArti
 			RepositoryID: art.RepoID,
 			HeadSha:      art.CommitSHA,
 		},
-	}, nil
+	}
 }
 
-func ToActionRunner(ctx context.Context, runner *actions_model.ActionRunner) *api.ActionRunner {
+func ToActionRunner(runner *actions_model.ActionRunner) *api.ActionRunner {
 	status := runner.Status()
 	apiStatus := "offline"
 	if runner.IsOnline() {