fix: address 54 MEDIUM/LOW priority PR review issues

Comprehensive fixes across Python code, shell scripts, and documentation
addressing all remaining MEDIUM and LOW priority review comments.

Python Code Fixes (27 fixes):
- tools/info.py: Simplified dispatch with lookup tables, defensive guards,
  CPU fallback formatting, !s conversion flags, module-level sync assertion
- tools/docker.py: Case-insensitive container ID regex, keyword-only confirm,
  module-level ALL_ACTIONS constant
- tools/virtualization.py: Normalized single-VM dict responses, unified
  list/details queries
- core/client.py: Fixed HTTP client singleton race condition, compound key
  substring matching for sensitive data redaction
- subscriptions/: Extracted SSL context creation to shared helper in utils.py,
  replaced deprecated ssl._create_unverified_context API
- tools/array.py: Renamed parity_history to parity_status, hoisted ALL_ACTIONS
- tools/storage.py: Fixed dict(None) risks, temperature 0 falsiness bug
- tools/notifications.py, keys.py, rclone.py: Fixed dict(None) TypeError risks
- tests/: Fixed generator type annotations, added coverage for compound keys

Shell Script Fixes (13 fixes):
- dashboard.sh: Dynamic server discovery, conditional debug output, null-safe
  jq, notification count guard order, removed unused variables
- unraid-query.sh: Proper JSON escaping via jq, --ignore-errors and --insecure
  CLI flags, TLS verification now on by default
- validate-marketplace.sh: Removed unused YELLOW variable, defensive jq,
  simplified repository URL output

Documentation Fixes (24+ fixes):
- Version consistency: Updated all references to v0.2.0 across pyproject.toml,
  plugin.json, marketplace.json, MARKETPLACE.md, __init__.py, README files
- Tool count updates: Changed all "26 tools" references to "10 tools, 90 actions"
- Markdown lint: Fixed MD022, MD031, MD047 issues across multiple files
- Research docs: Fixed auth headers, removed web artifacts, corrected stale info
- Skills docs: Fixed query examples, endpoint counts, env var references

All 227 tests pass, ruff and ty checks clean.

unraid_mcp/tools/notifications.py

@@ -12,6 +12,7 @@ from ..config.logging import logger
 from ..core.client import make_graphql_request
 from ..core.exceptions import ToolError
 
+
 QUERIES: dict[str, str] = {
     "overview": """
         query GetNotificationsOverview {
@@ -124,8 +125,8 @@ def register_notifications_tool(mcp: FastMCP) -> None:
 
             if action == "overview":
                 data = await make_graphql_request(QUERIES["overview"])
-                notifications = data.get("notifications", {})
-                return dict(notifications.get("overview", {}))
+                notifications = data.get("notifications") or {}
+                return dict(notifications.get("overview") or {})
 
             if action == "list":
                 filter_vars: dict[str, Any] = {
@@ -200,6 +201,6 @@ def register_notifications_tool(mcp: FastMCP) -> None:
             raise
         except Exception as e:
             logger.error(f"Error in unraid_notifications action={action}: {e}", exc_info=True)
-            raise ToolError(f"Failed to execute notifications/{action}: {str(e)}") from e
+            raise ToolError(f"Failed to execute notifications/{action}: {e!s}") from e
 
     logger.info("Notifications tool registered successfully")