test(api): cover --workers CLI branch and factory metrics path

Raise diff coverage above target by exercising the previously untested
lines:

- test_cli.py: invoke the `api` command with uvicorn.run mocked to assert
  the default path passes the app object (no workers/factory) and that
  --workers / API_WORKERS launches the env factory by import string with
  the requested worker count and factory=True.
- test_app_factory.py: add METRICS_ENABLED true/false cases that toggle
  the /metrics route, covering the env-bool parsing branch.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_api/test_app_factory.py

@@ -65,3 +65,19 @@ def test_factory_redis_enabled_accepts_truthy_values(clean_env):
     clean_env.setenv("REDIS_ENABLED", "1")
     app = create_app_from_env()
     assert app.state.redis_enabled is True
+
+
+def test_factory_metrics_enabled_via_env(clean_env):
+    """METRICS_ENABLED=true mounts the /metrics endpoint."""
+    clean_env.setenv("METRICS_ENABLED", "true")
+    app = create_app_from_env()
+    paths = {getattr(route, "path", None) for route in app.routes}
+    assert "/metrics" in paths
+
+
+def test_factory_metrics_disabled_via_env(clean_env):
+    """METRICS_ENABLED=false omits the /metrics endpoint."""
+    clean_env.setenv("METRICS_ENABLED", "false")
+    app = create_app_from_env()
+    paths = {getattr(route, "path", None) for route in app.routes}
+    assert "/metrics" not in paths

tests/test_api/test_cli.py

@@ -0,0 +1,49 @@
+"""Tests for the API CLI command (server launch wiring)."""
+
+from unittest.mock import patch
+
+from click.testing import CliRunner
+
+from meshcore_hub.api.cli import api
+
+
+def test_api_default_runs_single_process():
+    """With the default worker count, the app object is passed directly and no
+    worker/factory options are used."""
+    runner = CliRunner()
+    with patch("uvicorn.run") as mock_run:
+        result = runner.invoke(api, [], catch_exceptions=False)
+
+    assert result.exit_code == 0
+    assert mock_run.call_count == 1
+    args, kwargs = mock_run.call_args
+    # Single-process path passes the built app object, not an import string.
+    assert not isinstance(args[0], str)
+    assert "workers" not in kwargs
+
+
+def test_api_workers_uses_env_factory_import_string():
+    """workers > 1 launches uvicorn against the env-driven factory by import
+    string with the requested worker count."""
+    runner = CliRunner()
+    with patch("uvicorn.run") as mock_run:
+        result = runner.invoke(api, ["--workers", "3"], catch_exceptions=False)
+
+    assert result.exit_code == 0
+    args, kwargs = mock_run.call_args
+    assert args[0] == "meshcore_hub.api.app:create_app_from_env"
+    assert kwargs["workers"] == 3
+    assert kwargs["factory"] is True
+
+
+def test_api_workers_from_env_var():
+    """API_WORKERS env var drives the worker count (the Docker path)."""
+    runner = CliRunner()
+    with patch("uvicorn.run") as mock_run:
+        result = runner.invoke(
+            api, [], env={"API_WORKERS": "2"}, catch_exceptions=False
+        )
+
+    assert result.exit_code == 0
+    _, kwargs = mock_run.call_args
+    assert kwargs["workers"] == 2