security: bandit fixes B310/B324/B110 + QuietHTTPServer (#354)

* security: fix bandit security issues (B310, B324)

- Add usedforsecurity=False to MD5 hash in gateway_watcher.py
- Add URL scheme validation to prevent file:// access in config.py
- Add URL validation to bootstrap.py health check
- Add nosec comments where runtime validation exists

* fix: handle ConnectionResetError gracefully and add debug logging

- Add QuietHTTPServer class to suppress noisy connection reset errors
  caused by clients disconnecting abruptly (fixes log spam from
  'ConnectionResetError: [Errno 54] Connection reset by peer')

- Replace silent 'pass' statements with logger.debug() calls across
  api/auth.py, api/config.py, api/gateway_watcher.py, api/models.py,
  and api/onboarding.py for better observability during troubleshooting

- All tests pass (25 passed in test_regressions.py)

* chore: add debug logging to profiles and routes modules

- Replace silent 'pass' statements with logger.debug() calls in
  api/profiles.py for better error visibility during profile switching
  and module patching

- Add logger initialization to api/routes.py

* security: fix B110 bare except/pass issues (bandit security scan)

- Replace bare except/pass patterns with logger.debug() calls
- Fixes CWE-703 (improper check/handling of exceptional conditions)
- Files affected: routes.py, state_sync.py, streaming.py, workspace.py, server.py
- All tests pass successfully

* security: bandit fixes B310/B324/B110 + QuietHTTPServer (#354)

- api/gateway_watcher.py: MD5 usedforsecurity=False (B324)
- api/config.py, bootstrap.py: URL scheme validation before urlopen (B310)
- 12 files: replace bare except/pass with logger.debug() (B110)
- server.py: QuietHTTPServer suppresses client disconnect log noise
- server.py: fix sys.exc_info() (was traceback.sys.exc_info(), impl detail)
- tests/test_sprint43.py: 19 new tests covering all security fixes
- CHANGELOG.md: v0.50.14 entry; 841 tests total (up from 822)

---------

Co-authored-by: lawrencel1ng <lawrence.ling@global.ntt>
Co-authored-by: Nathan Esquenazi <nesquena@gmail.com>

CHANGELOG.md

@@ -5,6 +5,16 @@
 
 ---
 
+## [v0.50.14] Security fixes: B310 urlopen scheme validation, B324 MD5 usedforsecurity, B110 bare except logging + QuietHTTPServer (PR #354)
+
+- **B324 — MD5 no longer triggers crypto warnings** (`api/gateway_watcher.py`): `_snapshot_hash` uses MD5 only as a non-cryptographic change-detection hash. Added `usedforsecurity=False` so systems with strict crypto policies (FIPS mode etc.) don't reject the call.
+- **B310 — urlopen now validates URL scheme** (`api/config.py`, `bootstrap.py`): Both `get_available_models()` and `wait_for_health()` validate that the URL scheme is `http` or `https` before calling `urllib.request.urlopen`, preventing `file://` or other dangerous scheme injection. Added `# nosec B310` suppression after each validated call.
+- **B110 — bare `except: pass` blocks replaced with `logger.debug()`** (12 files): All `except Exception: pass` and `except: pass` blocks now log the failure at DEBUG level so operators can diagnose issues in production without changing behavior. A module-level `logger = logging.getLogger(__name__)` was added to each file.
+- **`QuietHTTPServer`** (`server.py`): Subclass of `ThreadingHTTPServer` that overrides `handle_error()` to silently drop `ConnectionResetError`, `BrokenPipeError`, `ConnectionAbortedError`, and socket errno 32/54/104 (client disconnect races). Real errors still delegate to the default handler. Reduces log spam from SSE clients that disconnect mid-stream.
+- **Session title redaction** (`api/routes.py`): The `/api/sessions` list endpoint now applies `_redact_text` to session titles before returning them, consistent with the per-session `redact_session_data()` already applied elsewhere.
+- **Fix**: `QuietHTTPServer.handle_error` uses `sys.exc_info()` (standard library) not `traceback.sys.exc_info()` (implementation detail); `sys` is now explicitly imported in `server.py`.
+  - 19 new tests in `tests/test_sprint43.py`; 841 tests total (up from 822)
+
 ## [v0.50.13] Fix session_search in WebUI sessions — inject SessionDB into AIAgent (PR #356)
 
 - **`session_search` now works in WebUI sessions** (`api/streaming.py`): The agent's `session_search` tool returned "Session database not available" for all WebUI sessions. The CLI and gateway code paths both initialize a `SessionDB` instance and pass it via `session_db=` to `AIAgent.__init__()`, but the WebUI streaming path was missing this step. `_run_agent_streaming` now initializes `SessionDB()` before constructing the agent and passes it in. A `try/except` wrapper makes the init non-fatal — if `hermes_state` is unavailable (older installs, test environments), a `WARNING` is printed and `session_db=None` is passed instead, preserving the prior behavior gracefully.