refactor: break up self_reflect into helpers

Extract _format_recurring_topics() and _build_reflection_report() from
self_reflect(), reducing it from 67 lines to 18. No behavior change.

Fixes #640

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/timmy/session_logger.py

@@ -392,31 +392,26 @@ def _build_insights(
     return insights or ["Conversations look healthy. Keep up the good work."]
 
 
-def self_reflect(limit: int = 30) -> str:
-    """Review recent conversations and reflect on Timmy's own behavior.
+def _format_recurring_topics(repeated: list[tuple[str, int]]) -> list[str]:
+    """Format the recurring-topics section of the reflection report."""
+    if repeated:
+        lines = ["### Recurring Topics"]
+        for word, count in repeated:
+            lines.append(f'- "{word}" ({count} mentions)')
+        lines.append("")
+        return lines
+    return ["### Recurring Topics\nNo strong patterns detected.\n"]
 
-    Scans past session entries for patterns: low-confidence responses,
-    errors, repeated topics, and conversation quality signals.  Returns
-    a structured reflection that Timmy can use to improve.
 
-    Args:
-        limit: How many recent entries to review (default 30).
-
-    Returns:
-        A formatted self-reflection report.
-    """
-    sl = get_session_logger()
-    sl.flush()
-    entries = sl.get_recent_entries(limit=limit)
-
-    if not entries:
-        return "No conversation history to reflect on yet."
-
-    _messages, errors, timmy_msgs, user_msgs = _categorize_entries(entries)
-    low_conf = _find_low_confidence(timmy_msgs)
-    repeated = _find_repeated_topics(user_msgs)
-
-    # Build reflection report
+def _build_reflection_report(
+    entries: list[dict],
+    errors: list[dict],
+    timmy_msgs: list[dict],
+    user_msgs: list[dict],
+    low_conf: list[dict],
+    repeated: list[tuple[str, int]],
+) -> str:
+    """Assemble the full self-reflection report from analysed data."""
     sections: list[str] = ["## Self-Reflection Report\n"]
     sections.append(
         f"Reviewed {len(entries)} recent entries: "
@@ -446,16 +441,37 @@ def self_reflect(limit: int = 30) -> str:
         )
     )
 
-    if repeated:
-        sections.append("### Recurring Topics")
-        for word, count in repeated:
-            sections.append(f'- "{word}" ({count} mentions)')
-        sections.append("")
-    else:
-        sections.append("### Recurring Topics\nNo strong patterns detected.\n")
+    sections.extend(_format_recurring_topics(repeated))
 
     sections.append("### Insights")
     for insight in _build_insights(low_conf, errors, repeated):
         sections.append(f"- {insight}")
 
     return "\n".join(sections)
+
+
+def self_reflect(limit: int = 30) -> str:
+    """Review recent conversations and reflect on Timmy's own behavior.
+
+    Scans past session entries for patterns: low-confidence responses,
+    errors, repeated topics, and conversation quality signals.  Returns
+    a structured reflection that Timmy can use to improve.
+
+    Args:
+        limit: How many recent entries to review (default 30).
+
+    Returns:
+        A formatted self-reflection report.
+    """
+    sl = get_session_logger()
+    sl.flush()
+    entries = sl.get_recent_entries(limit=limit)
+
+    if not entries:
+        return "No conversation history to reflect on yet."
+
+    _messages, errors, timmy_msgs, user_msgs = _categorize_entries(entries)
+    low_conf = _find_low_confidence(timmy_msgs)
+    repeated = _find_repeated_topics(user_msgs)
+
+    return _build_reflection_report(entries, errors, timmy_msgs, user_msgs, low_conf, repeated)