refactor: replace bare catch(...) with specific exception handling (#49)

[Justxd22]

This PR addresses issue #49 by replacing bare catch(...) blocks with specific exception handling to prevent swallowing errors and improve debuggability.

Key changes

• In src/core/query_parser.cpp:
  • Caught nlohmann::json::parse_error specifically for JSON parsing operations.
  • Caught std::exception as a fallback for other errors.
  • Added debug/warning logs with the exception message.
• In src/core/query_generator.cpp:
  • Replaced catch(...) with catch(const std::exception&) in buildPrompt.
  • Added warning logs with the exception message.

Builds fine, all tests run okay .