fix(security): path traversal, timing-safe auth, stale credential bindings

Security:
- Remove /mnt/ from _ALLOWED_LOG_PREFIXES to prevent Unraid share exposure
- Add early .. detection for disk/logs and live/log_tail path validation
- Add /boot/ prefix restriction for flash_backup source_path
- Use hmac.compare_digest for timing-safe API key verification in server.py
- Gate include_traceback on DEBUG log level (no tracebacks in production)

Correctness:
- Re-raise CredentialsNotConfiguredError in health check instead of swallowing
- Fix ups_device query (remove non-existent nominalPower/currentPower fields)

Best practices (BP-01, BP-05, BP-06):
- Add # noqa: ASYNC109 to timeout params in _handle_live and unraid()
- Fix start_array* → start_array in docstring (not in ARRAY_DESTRUCTIVE)
- Remove from __future__ import annotations from snapshot.py
- Replace import-time UNRAID_API_KEY/URL bindings with _settings.ATTR pattern
  in manager.py, snapshot.py, utils.py, diagnostics.py — fixes stale binding
  after apply_runtime_config() post-elicitation (BP-05)

CI/CD:
- Add .github/workflows/ci.yml (5-job pipeline: lint, typecheck, test, version-sync, audit)
- Add fail_under = 80 to [tool.coverage.report]
- Add version sync check to scripts/validate-marketplace.sh

Documentation:
- Sync plugin.json version 1.1.1 → 1.1.2 with pyproject.toml
- Update CLAUDE.md: 3 tools, system domain count 18, scripts comment fix
- Update README.md: 3 tools, security notes
- Update docs/AUTHENTICATION.md: H1 title fix
- Add UNRAID_CREDENTIALS_DIR to .env.example

Bump: 1.1.1 → 1.1.2

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

unraid_mcp/subscriptions/snapshot.py

@@ -11,8 +11,6 @@ WebSocket per call. This is intentional: MCP tools are request-response.
 Use the SubscriptionManager for long-lived monitoring resources.
 """
 
-from __future__ import annotations
-
 import asyncio
 import json
 from typing import Any
@@ -20,8 +18,8 @@ from typing import Any
 import websockets
 from websockets.typing import Subprotocol
 
+from ..config import settings as _settings
 from ..config.logging import logger
-from ..config.settings import UNRAID_API_KEY
 from ..core.exceptions import ToolError
 from .utils import build_ws_ssl_context, build_ws_url
 
@@ -51,8 +49,8 @@ async def subscribe_once(
 
         # Handshake
         init: dict[str, Any] = {"type": "connection_init"}
-        if UNRAID_API_KEY:
-            init["payload"] = {"x-api-key": UNRAID_API_KEY}
+        if _settings.UNRAID_API_KEY:
+            init["payload"] = {"x-api-key": _settings.UNRAID_API_KEY}
         await ws.send(json.dumps(init))
 
         raw = await asyncio.wait_for(ws.recv(), timeout=timeout)
@@ -126,8 +124,8 @@ async def subscribe_collect(
         sub_id = "snapshot-1"
 
         init: dict[str, Any] = {"type": "connection_init"}
-        if UNRAID_API_KEY:
-            init["payload"] = {"x-api-key": UNRAID_API_KEY}
+        if _settings.UNRAID_API_KEY:
+            init["payload"] = {"x-api-key": _settings.UNRAID_API_KEY}
         await ws.send(json.dumps(init))
 
         raw = await asyncio.wait_for(ws.recv(), timeout=timeout)