Remove the #[ignore] gate from startup_banner_mentions_workflow_completions
by injecting a dummy ANTHROPIC_API_KEY. The test exercises LiveCli banner
rendering, not API calls. Cleanup env var after test.
Test suite now 102/102 in CLI crate (was 101 + 1 ignored).
Inject a dummy ANTHROPIC_API_KEY for
build_runtime_runs_plugin_lifecycle_init_and_shutdown so the test
exercises plugin init/shutdown without requiring real credentials.
The API client is constructed but never used for streaming.
Clean up the env var after the test to avoid polluting parallel tests.
Jobdori