v2.0.3: Improve error handling, add tests, cleanup

- Fix bare except clauses in curator.py and main.py
- Change embedding model to snowflake-arctic-embed2
- Increase semantic_score_threshold to 0.6
- Add memory context explanation to systemprompt.md
- Add pytest dependencies to requirements.txt
- Remove unused context_handler.py and .env.example
- Add project documentation (CLAUDE.md) and test files

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

requirements.txt

@@ -6,3 +6,5 @@ ollama>=0.1.0
 toml>=0.10.2
 tiktoken>=0.5.0
 apscheduler>=3.10.0
+pytest>=7.0.0
+pytest-asyncio>=0.21.0