feat(daemon): P1-06 health 응답 bridge_version 필드 추가

importlib.metadata.version("toss-browser-bridge") 로 패키지 메타데이터에서
version 추출 → BRIDGE_VERSION 모듈 상수에 캐시 → health() 응답 top-level
에 노출. PackageNotFoundError 시 "0.0.0+unknown" fallback.

financier-v2 wrapper(Phase 4 P4-06) 가 startup 시 minimum 버전 검증을
할 수 있도록 bridge 측 자기 버전 노출. SSOT 는 pyproject.toml,
__init__.py.__version__ + daemon.BRIDGE_VERSION 모두 거기서 파생.

3중 동기 검증 단위 테스트 1건 추가 (BRIDGE_VERSION == __version__).
영향받는 23 tests PASS. live e2e 봉인은 그대로 유지.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: heeho

src/toss_browser_bridge/daemon.py

@@ -9,6 +9,7 @@
 from datetime import datetime
 from http import HTTPStatus
 from http.server import BaseHTTPRequestHandler, HTTPServer
+from importlib.metadata import PackageNotFoundError, version as _pkg_version
 from typing import Any
 from urllib.parse import urlparse
 from zoneinfo import ZoneInfo
@@ -59,6 +60,16 @@
 FINAL_SUBMIT_ENABLE_ENV = "TOSS_BRIDGE_ENABLE_FINAL_SUBMIT"
 FINAL_SUBMIT_TEST_BYPASS_ENV = "TOSS_BRIDGE_ALLOW_TEST_FINAL_SUBMIT"
 
+
+def _resolve_bridge_version() -> str:
+    try:
+        return _pkg_version("toss-browser-bridge")
+    except PackageNotFoundError:
+        return "0.0.0+unknown"
+
+
+BRIDGE_VERSION = _resolve_bridge_version()
+
 BROKER_ACK_OK = "OK"
 BROKER_REJECTED_INSUFFICIENT_BALANCE = "BROKER_REJECTED_INSUFFICIENT_BALANCE"
 BROKER_REJECTED_INSUFFICIENT_QUANTITY = "BROKER_REJECTED_INSUFFICIENT_QUANTITY"
@@ -631,6 +642,7 @@ def health(self) -> dict[str, Any]:
             "source": SOURCE,
             "checked_at": context.checked_at,
             "capability": capability,
+            "bridge_version": BRIDGE_VERSION,
             "data": payload,
             "diagnostics": {
                 "endpoint_matrix": context.endpoint_matrix,

tests/test_packaging_metadata.py

@@ -25,3 +25,9 @@ def test_project_version_matches_runtime_version() -> None:
 
     assert pyproject["project"]["name"] == "toss-browser-bridge"
     assert pyproject["project"]["version"] == __version__
+
+
+def test_daemon_bridge_version_constant_matches_package_version() -> None:
+    from toss_browser_bridge.daemon import BRIDGE_VERSION
+
+    assert BRIDGE_VERSION == __version__