fix: replace 59 bare except clauses with proper logging (#25)

All `except Exception:` now catch as `except Exception as exc:` with
appropriate logging (warning for critical paths, debug for graceful degradation).

Added logger setup to 4 files that lacked it:
- src/timmy/memory/vector_store.py
- src/dashboard/middleware/csrf.py
- src/dashboard/middleware/security_headers.py
- src/spark/memory.py

31 files changed across timmy core, dashboard, infrastructure, integrations.
Zero bare excepts remain. 1340 tests passing.

src/dashboard/routes/chat_api.py

@@ -51,7 +51,8 @@ async def api_chat(request: Request):
 
     try:
         body = await request.json()
-    except Exception:
+    except Exception as exc:
+        logger.warning("Chat API JSON parse error: %s", exc)
         return JSONResponse(status_code=400, content={"error": "Invalid JSON"})
 
     messages = body.get("messages")