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>

docs/research/unraid-api-crawl.md

@@ -713,6 +713,23 @@ type Mutation {
     addUser(input: addUserInput!): User
     deleteUser(input: deleteUserInput!): User
 }
+
+type ApiKeyMutations {
+    """Create an API key"""
+    create(input: CreateApiKeyInput!): ApiKey!
+
+    """Add a role to an API key"""
+    addRole(input: AddRoleForApiKeyInput!): Boolean!
+
+    """Remove a role from an API key"""
+    removeRole(input: RemoveRoleFromApiKeyInput!): Boolean!
+
+    """Delete one or more API keys"""
+    delete(input: DeleteApiKeyInput!): Boolean!
+
+    """Update an API key"""
+    update(input: UpdateApiKeyInput!): ApiKey!
+}
 ```
 
 > **Note:** The client schema above uses `ID!` for disk mutation args (e.g., `mountArrayDisk(id: ID!)`), but the actual server resolvers use `PrefixedID!`. The MCP tool code correctly uses `PrefixedID!` based on server source analysis.