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>

app/main.py

@@ -80,7 +80,8 @@ async def health_check():
             resp = await client.get(f"{config.ollama_host}/api/tags")
             if resp.status_code == 200:
                 ollama_status = "reachable"
-    except: pass
+    except Exception:
+        logger.warning(f"Failed to reach Ollama at {config.ollama_host}")
     return {"status": "ok", "ollama": ollama_status}