Add eprintln! logging before fallback values in 7 files where errors
were previously swallowed without visibility:
- [stream] malformed JSON chunk, missing usage tokens, missing tool call index
- [mcp] missing result fields, client builder failure, response body read error
- [subagent] missing API key in settings, all resolution paths exhausted
- [state] memory_dir no-parent, session_id missing, lock poisoned, store_base_dir
- [input] missing default_model for provider
- [session] corrupt agents.json parse failure
- [pkce] clock-before-epoch on random byte generation
All fallback values are preserved — this adds observability without
changing behavior for callers.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- Implemented `LessonExport` and `LessonImport` actions in the action module.
- Added corresponding command parsing for lesson export and import.
- Created functions to handle lesson export and import in the memory module.
- Updated state management to reflect changes after lesson operations.
- Introduced deferred operations for handling asynchronous tasks in the event loop.
- Enhanced the tool execution context to include graduated checks for file operations.
- Added OAuth support with PKCE for secure authorization flows.
- Implemented a loopback server for handling OAuth redirects.
- Refactored various modules to improve code organization and maintainability.
