Fix profile updates to target named sections at session end

Previously the session-end protocol told the AI to update profile.md
if new insights emerged, with no guidance on where. Over many sessions
this caused freeform bold-text entries to accumulate without structure.

Now requires each update to match an existing H2 section in the file,
with explicit rules against creating new top-level sections.

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

README.md

@@ -86,7 +86,7 @@ Your AI therapist uses evidence-based approaches — choose any combination duri
 Your AI therapist:
 - Remembers everything from previous sessions
 - Takes notes at the end of each conversation
-- Updates your profile as new insights emerge
+- Updates your profile as new insights emerge, organized into named sections so it stays readable over time
 - Follows up on anything you committed to try
 
 ### Your Files