feat: harden API safety and expand command docs with full test coverage

unraid_mcp/core/exceptions.py

@@ -15,26 +15,31 @@ class ToolError(FastMCPToolError):
 
     Inherits from FastMCP's ToolError to ensure proper MCP protocol handling.
     """
+
     pass
 
 
 class ConfigurationError(ToolError):
     """Raised when there are configuration-related errors."""
+
     pass
 
 
 class UnraidAPIError(ToolError):
     """Raised when the Unraid API returns an error or is unreachable."""
+
     pass
 
 
 class SubscriptionError(ToolError):
     """Raised when there are WebSocket subscription-related errors."""
+
     pass
 
 
 class ValidationError(ToolError):
     """Raised when input validation fails."""
+
     pass
 
 
@@ -45,4 +50,5 @@ class IdempotentOperationError(ToolError):
     which should typically be converted to a success response rather than
     propagated as an error to the user.
     """
+
     pass