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>

src/bridge/health.py

@@ -0,0 +1,31 @@
+"""HTTP health checker for OpsBridge."""
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import Optional
+
+import httpx
+
+
+@dataclass
+class HealthResult:
+    ok: bool
+    status_code: Optional[int] = None
+    error: Optional[str] = None
+
+
+class HealthChecker:
+    def __init__(self, url: str, timeout_seconds: int = 5):
+        self._url = url
+        self._timeout = timeout_seconds
+
+    async def check(self) -> HealthResult:
+        try:
+            async with httpx.AsyncClient(timeout=self._timeout) as client:
+                response = await client.get(self._url)
+                response.raise_for_status()
+                return HealthResult(ok=True, status_code=response.status_code)
+        except httpx.HTTPStatusError as e:
+            return HealthResult(ok=False, status_code=e.response.status_code, error=str(e))
+        except Exception as e:
+            return HealthResult(ok=False, error=str(e))