style(13-03): apply Prettier formatting across repo

Mechanical reformat — no logic changes. 398 files changed, 19125
insertions(+), 16457 deletions(-). Prettier 3.8.4 with .prettierrc
(singleQuote:true, semi:true, tabWidth:2, trailingComma:all,
printWidth:100). Isolated per D-13-08 for reviewability.

.planning/notes/familysync-architecture.md

@@ -9,6 +9,7 @@ context: Exploration + verification sessions — reasoning captured before proje
 ## What we're building
 
 A self-hosted family organization hub, modeled loosely on Skylight, with two concerns:
+
 1. **Shared calendar** — one family calendar everyone can see and edit, surfaced natively
    where possible and in a custom app everywhere else
 2. **Shared collaborative lists** — grocery lists, gift ideas, anything co-edited
@@ -47,7 +48,7 @@ reach.
   native read-write. Not required.
 
 **Why not Baikal (self-hosted CalDAV)?** It was the prior pick, now dropped. The Fastmail Android
-app cannot display a self-hosted CalDAV calendar, so Baikal bought *me* nothing on Android — it
+app cannot display a self-hosted CalDAV calendar, so Baikal bought _me_ nothing on Android — it
 only helped Apple members, who are equally served by the PWA. Fastmail-hosted gives the whole
 household native-or-PWA access with one fewer self-hosted service.
 
@@ -100,7 +101,7 @@ lowest-friction path for non-technical household members (one PWA).
 ## Open questions
 
 - Fastmail API: JMAP vs CalDAV for the app's calendar read/write — which is cleaner to build against?
-- Aggregating Apple members' *personal* calendars into the display — via shared CalDAV/ICS, or skip
+- Aggregating Apple members' _personal_ calendars into the display — via shared CalDAV/ICS, or skip
   and only show the shared family calendar?
 - PWA push notifications: sufficient for family alerts, or need something else?