feat: implement OpsBridge CLI (BRIDGE-WP-0001)

Full TDD implementation of the `bridge` CLI tool covering all phases
from BRIDGE-WP-0001: project scaffolding, config loading, state
management, audit logging, health checks, tunnel lifecycle manager, and
all CLI commands (up/down/restart/status/logs). 77 tests, all green.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_health.py

@@ -0,0 +1,78 @@
+"""Tests for health checking."""
+import pytest
+from unittest.mock import MagicMock, patch, AsyncMock
+
+from bridge.health import HealthChecker, HealthResult
+
+
+class TestHealthResult:
+    def test_ok(self):
+        r = HealthResult(ok=True, status_code=200)
+        assert r.ok
+        assert r.status_code == 200
+        assert r.error is None
+
+    def test_failure(self):
+        r = HealthResult(ok=False, error="connection refused")
+        assert not r.ok
+        assert r.error == "connection refused"
+
+
+class TestHealthChecker:
+    @pytest.mark.asyncio
+    async def test_check_ok(self):
+        checker = HealthChecker(url="http://127.0.0.1:18000/health", timeout_seconds=5)
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_response.raise_for_status = MagicMock()
+
+        with patch("httpx.AsyncClient") as mock_client_cls:
+            mock_client = AsyncMock()
+            mock_client.__aenter__ = AsyncMock(return_value=mock_client)
+            mock_client.__aexit__ = AsyncMock(return_value=False)
+            mock_client.get = AsyncMock(return_value=mock_response)
+            mock_client_cls.return_value = mock_client
+
+            result = await checker.check()
+
+        assert result.ok
+        assert result.status_code == 200
+
+    @pytest.mark.asyncio
+    async def test_check_connection_error(self):
+        import httpx
+        checker = HealthChecker(url="http://127.0.0.1:19999/health", timeout_seconds=1)
+
+        with patch("httpx.AsyncClient") as mock_client_cls:
+            mock_client = AsyncMock()
+            mock_client.__aenter__ = AsyncMock(return_value=mock_client)
+            mock_client.__aexit__ = AsyncMock(return_value=False)
+            mock_client.get = AsyncMock(side_effect=httpx.ConnectError("refused"))
+            mock_client_cls.return_value = mock_client
+
+            result = await checker.check()
+
+        assert not result.ok
+        assert result.error is not None
+
+    @pytest.mark.asyncio
+    async def test_check_http_error(self):
+        import httpx
+        checker = HealthChecker(url="http://127.0.0.1:18000/health", timeout_seconds=5)
+        mock_response = MagicMock()
+        mock_response.status_code = 503
+        mock_response.raise_for_status = MagicMock(
+            side_effect=httpx.HTTPStatusError("503", request=MagicMock(), response=mock_response)
+        )
+
+        with patch("httpx.AsyncClient") as mock_client_cls:
+            mock_client = AsyncMock()
+            mock_client.__aenter__ = AsyncMock(return_value=mock_client)
+            mock_client.__aexit__ = AsyncMock(return_value=False)
+            mock_client.get = AsyncMock(return_value=mock_response)
+            mock_client_cls.return_value = mock_client
+
+            result = await checker.check()
+
+        assert not result.ok
+        assert result.status_code == 503