- 'Learning Harness' wordmark → 'LH' (the owner's header in the mockup;
flagged as a copy change — it's visually the same brand mark).
- New session: + NEW SESSION row wired with one POST /api/chats then
navigate (the mock drew it as visual-only; POST already existed).
- Search: a SESSIONS label + inline input filtering the polled snapshot
client-side (title substring, no server round trip).
- Skin: sidebar stays bg-background with the edge #434343 border-r; the
selected row now carries the rounding + borders from the raised
surface #1C1C1C via accent tokens.