feat: add 5 notification mutations + comprehensive refactors from PR review

New notification actions (archive_many, create_unique, unarchive_many,
unarchive_all, recalculate) bring unraid_notifications to 14 actions.

Also includes continuation of CodeRabbit/PR review fixes:
- Remove redundant try-except in virtualization.py (silent failure fix)
- Add QueryCache protocol with get/put/invalidate_all to core/client.py
- Refactor subscriptions (manager, diagnostics, resources, utils)
- Update config (logging, settings) for improved structure
- Expand test coverage: http_layer, safety guards, schema validation
- Minor cleanups: array, docker, health, keys tools

Co-authored-by: Claude <noreply@anthropic.com>

unraid_mcp/tools/array.py

@@ -73,7 +73,7 @@ def register_array_tool(mcp: FastMCP) -> None:
         """Manage Unraid array parity checks.
 
         Actions:
-          parity_start - Start parity check (optional correct=True to fix errors)
+          parity_start - Start parity check (correct=True to fix errors, correct=False for read-only; required)
           parity_pause - Pause running parity check
           parity_resume - Resume paused parity check
           parity_cancel - Cancel running parity check