test(e2e): cover host mode, reusable workflows, scheduling, reconnect and CLI flags (#1347)

Extends the e2e suite with scenarios for host labels, local `workflow_call`, label routing, `runner.capacity`, a dropped and restored connection to Gitea, and the daemon's `--once`, `--labels` and `shutdown_timeout` behaviour.

Stacked on https://gitea.com/gitea/runner/pulls/1346, so its commit shows here until that merges. The new scenarios pass locally against gitea/gitea:latest and main-nightly.

Assisted-by: Codet:codet
Co-authored-by: Zettat123 <[email protected]>
Co-authored-by: bircni <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1347
Reviewed-by: Zettat123 <[email protected]>

DEVELOPMENT.md

@@ -59,8 +59,10 @@ Each lives in `internal/pkg/action/<name>` and is registered in `builtinActions`
 It requires Docker and is excluded from `make test`. CI runs stable and nightly variants in
 parallel.
 
-The `cli_register_daemon` scenario builds the binary and drives `register` and `daemon` as a user would. The
-`failure_paths` scenario covers failed, skipped, tolerated and timed-out jobs.
+The `cli_*` scenarios build the binary and drive `register` and `daemon` as a user would, including `--once`,
+`--labels` and shutdown with a running job. `failure_paths` covers failed, skipped, tolerated and timed-out jobs.
+`label_routing` and `capacity` cover scheduling, `reconnect` drops the connection to Gitea through a proxy, and
+`host_mode` and `reusable_workflow` cover host labels and `workflow_call`.
 
 The suite shares one Gitea and regular runner. Cache and ephemeral scenarios use isolated
 repository runners. A run path is `<workflow>@<ref>` and a log row is `<timestamp>Z <payload>`.