Fix AttributeError on bullet lines in extract_memory_from_chat (#873)

The fallback memory extractor (used by routes/memory_routes.py when the LLM
extractor fails) matched list items with `r'^[-*•]|\d+\.\s*(.*)'`. Operator
precedence makes that `(^[-*•]) | (\d+\.\s*(.*))`, so the capture group only
exists on the numbered-list branch.

A bullet line ("- foo") matches the first branch, so `group(1)` is None and
`text_match.group(1).strip()` raises AttributeError — crashing extraction for
any assistant message that contains a bullet list (i.e. most of them). Numbered
lists happened to work.

Group both markers — `r'^(?:[-*•]|\d+\.)\s*(.*)'` — so the capture applies to
bullets and numbers alike.

Adds tests/test_memory_bullet_extraction.py (red before, green after).

src/memory.py

@@ -59,8 +59,12 @@ class MemoryManager:
                     line = line.strip()
                     # Look for bullet points or numbered lists that might contain memories
                     if re.match(r'^[-*•]|\d+\.', line):
-                        # Extract the text after the bullet/number
-                        text_match = re.match(r'^[-*•]|\d+\.\s*(.*)', line)
+                        # Extract the text after the bullet/number. Group both
+                        # markers so the capture applies to either — the previous
+                        # `^[-*•]|\d+\.\s*(.*)` put the group on the numbered branch
+                        # only, so a bullet line matched with group(1)=None and
+                        # crashed on .strip().
+                        text_match = re.match(r'^(?:[-*•]|\d+\.)\s*(.*)', line)
                         if text_match:
                             text = text_match.group(1).strip()
                             if text: