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/middleware/csrf.py

@@ -5,6 +5,7 @@ to protect state-changing endpoints from cross-site request attacks.
 """
 
 import hmac
+import logging
 import secrets
 from collections.abc import Callable
 from functools import wraps
@@ -16,6 +17,8 @@ from starlette.responses import JSONResponse, Response
 # Module-level set to track exempt routes
 _exempt_routes: set[str] = set()
 
+logger = logging.getLogger(__name__)
+
 
 def csrf_exempt(endpoint: Callable) -> Callable:
     """Decorator to mark an endpoint as exempt from CSRF validation.
@@ -278,7 +281,8 @@ class CSRFMiddleware(BaseHTTPMiddleware):
                 form_token = form_data.get(self.form_field)
                 if form_token and validate_csrf_token(str(form_token), csrf_cookie):
                     return True
-            except Exception:
+            except Exception as exc:
+                logger.debug("CSRF form parsing error: %s", exc)
                 # Error parsing form data, treat as invalid
                 pass