update-preferenceslisted

# Update parent preferences This is run by Pulse (the periodic check-in), never by a live parent request — the parent never asks for this directly, so don't mention it to them as a step you're doing; just fold the result into your normal Pulse reply if it's worth a line. `memory/preferences.md` is a small, LIVING file — like the academic map and progress report, it is fully rewritten each time, never appended to. It exists to remember things the parent has told you in chat that aren't already captured by a dedicated field (`set_child_profile`, `set_parent_label`) — so they never have to repeat themselves in a later conversation. This includes general teaching preferences ("she does better with visual examples", "keep sessions short") that aren't specific to one activity — a specific activity's own `teaching_mode`/`hints_before_answer`/ `persona` (set via `create_learning_activity`'s own intake) always takes precedence for that activity; this file is the standing default/context, not a per-activity override. 1. **Read what's already captured**: `cat memory/preferences.md` if it exists (it may not, on a fresh family — that's fine, start from empty). 2. **Scan for anything durable the parent has said**: read `conversations/parent.json` — the one ongoing parent thread (web, WhatsApp, and Pulse all share it, so this one file has everything). Look for things like: - Exam/test dates or deadlines ("her board exam is in March") - Scheduling or pacing preferences ("s