feat: doctor visit log, schedule prediction, chart PDF, natural digest

- Doctor notes: add doctorName, reason, prescriptions, nextAppointmentAt fields (schema + API + UI)
- Dashboard: baby schedule prediction widget (avg nap/bedtime/first-feed over 14 days)
- Growth PDF: embed weight chart as image (SVG→Canvas capture) before data table
- Weekly digest: natural language push notification instead of bullet stats

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

IMPROVEMENTS.md

@@ -73,10 +73,10 @@
 
 - [x] **Vaccination tracker** — full UI + API, overdue badges, done/upcoming sections
 - [x] **Teeth tracker** — visual grid of 20 baby teeth, tap to mark appeared (in progress)
-- [ ] **Doctor visit log** — notes, prescriptions, next appointment date
-- [ ] **Baby schedule prediction** — "usually naps around 14h30" from historical patterns
-- [ ] **Growth chart in PDF** — embed chart image (jsPDF canvas) not just table
-- [ ] **Natural language digest** — "Emma feeds every 2h45 on average" weekly push
+- [x] **Doctor visit log** — notes, prescriptions, next appointment date
+- [x] **Baby schedule prediction** — "usually naps around 14h30" from historical patterns
+- [x] **Growth chart in PDF** — embed chart image (jsPDF canvas) not just table
+- [x] **Natural language digest** — "Emma feeds every 2h45 on average" weekly push
 - [ ] **Wellness check-in** — parent self-reports sleep/mood for postpartum monitoring
 - [ ] **Weight gain on-track indicator** — projected line on growth chart
 - [ ] **Contraction timer** — repurpose timer infra for pre-birth use