fix(exec): load local reusable workflows from disk with --no-skip-checkout (#1362)

`gitea-runner exec --no-skip-checkout` panics with a nil pointer dereference on any job that calls a local reusable workflow (`uses: ./.gitea/workflows/x.yml`).

Fetching a local reusable workflow from the instance was gated on `NoSkipCheckout`, but it reads the repository and SHA from the task's preset context, which only the daemon has. `exec` always has the workflow on disk, so the fetch is now gated on the preset instead, and `--no-skip-checkout` only governs checkout again. Daemon behavior is unchanged.

The `exec` e2e test now also runs the existing reusable caller/callee pair with `--no-skip-checkout`.

Reviewed-on: https://gitea.com/gitea/runner/pulls/1362
Reviewed-by: Lunny Xiao <[email protected]>
Co-authored-by: silverwind <[email protected]>

e2e/compatibility_test.go

@@ -30,7 +30,7 @@ func TestCompatibility(t *testing.T) {
 	t.Run("cancellation_and_log_streaming", testRunCancellation)
 	t.Run("dispatch", testWorkflowDispatch)
 	t.Run("builtin_checkout", testBuiltinCheckout)
-	t.Run("exec_artifacts", testExecArtifacts)
+	t.Run("exec", testExec)
 	t.Run("moving_action_ref", testMovingActionRef)
 	t.Run("ephemeral", testEphemeralRunner)
 	t.Run("failure_paths", testFailurePaths)