v2.0.1 – Stable reflection queries and example cleanup

This release finalizes reflection-based query stability and resolves several
edge cases in coroutine and lambda usage under GCC 13+.

🧩 Core Changes

• Fixed internal compiler errors triggered by local struct definitions and
  inline std::tuple with std::optional inside coroutines.
• Reflection-based queries (query_reflect, exec_reflect) are now fully
  stable and GCC-compatible.
• Adjusted reflection mapper to correctly handle aggregates passed from
  lambdas and transactions.

⚙️ Example & Schema

• Updated example to remove all local struct definitions.
• Replaced tuple inserts with aggregate-based inserts for clarity.
• Fixed invalid SQL in ensure_schema() (extra semicolons removed).
• Added explicit std::string conversion in query_awaitable() calls to
  support C++23’s explicit string_view constructor.

🔒 Reliability

• Safe connection cleanup added in run_notifications().
• Verified transaction rollback/commit behavior under nested SAVEPOINTs.

✅ Result

Upq now builds cleanly with GCC 13+, Clang 17+, and MSVC 2022.
Reflection queries are production-stable