fix(memory): record dislikes as dislikes, not preferences (#2435)

_fallback_memory_candidates matched both positive (prefer/like/love) and
negative (hate / do not like / don't like) sentiment verbs in one regex
alternation, then formatted every hit as "User prefers {X}.". So
"I hate cilantro" was stored as "User prefers cilantro." -- the inverse of
what the user said. These fallback facts are persisted to memory and later
re-injected into the model's context, so the inverted preference actively
misleads the assistant.

Capture the matched verb and branch on it: negatives become
"User dislikes {X}.", positives stay "User prefers {X}." (still filed under
the existing "preference" category).

Supported by Claude Opus 4.8

Co-authored-by: SurprisedDuck <288741682+SurprisedDuck@users.noreply.github.com>

services/memory/memory_extractor.py

@@ -192,11 +192,19 @@ def _fallback_memory_candidates(messages) -> list[dict]:
             if place:
                 add(f"User lives in {place}.", "identity")
 
-        m = re.search(r"\bi (?:prefer|like|love|hate|do not like|don't like)\s+([^.!?\n]{4,100})", text, re.I)
+        m = re.search(r"\bi (prefer|like|love|hate|do not like|don't like)\s+([^.!?\n]{4,100})", text, re.I)
         if m:
-            preference = _clean_memory_value(m.group(1), 100)
+            preference = _clean_memory_value(m.group(2), 100)
             if preference:
-                add(f"User prefers {preference}.", "preference")
+                # The same pattern catches likes and dislikes; keep the stored
+                # sentiment faithful instead of recording every match as a
+                # preference ("I hate cilantro" must not become "User prefers
+                # cilantro").
+                verb = m.group(1).lower()
+                if verb in ("hate", "do not like", "don't like"):
+                    add(f"User dislikes {preference}.", "preference")
+                else:
+                    add(f"User prefers {preference}.", "preference")
 
         m = re.search(
             r"\bi (?:(?:want|would like|plan|hope) to|wanna) "