feat: debug-only type verification for materialized values

[zharinov]

Summary

• Add debug_verify_type() that validates materialized Value matches declared bytecode type
• Zero-cost in release builds via #[cfg(debug_assertions)]
• On mismatch, panics with pretty diagnostic showing expected .d.ts types, actual JSON output, and error paths

Example output

================================================================================
TYPE MISMATCH: Query output does not match declared type
================================================================================

export interface Node {
  kind: string;
  text: string;
  span: [number, number];
}

export interface Q {
  id: Node;
}

---------------------------------- Output: Q -----------------------------------

{
  "id": "wrong"
}

----------------------------------- Details ------------------------------------

id: expected Node, found string

================================================================================

Testing

• 16 new tests covering valid cases (should not panic) and invalid cases (#[should_panic])