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/research/questions.md

@@ -3,6 +3,7 @@
 ## Open
 
 ### RQ-003 — Fastmail calendar API: JMAP vs CalDAV
+
 **Question**: For the custom app to read AND write the shared family calendar on Fastmail, is JMAP
 or CalDAV the cleaner integration? Can a scoped Fastmail API token grant calendar read-write without
 exposing the full account?
@@ -19,6 +20,7 @@ create/update/delete works via token. Compare to CalDAV (sabre-dav style) effort
 ## Resolved
 
 ### RQ-001 — Vikunja MariaDB compatibility — SUPERSEDED
+
 Vikunja was dropped from the architecture (lists now live in the custom app's own MariaDB). The
 MariaDB findings still apply to the custom app itself: use MariaDB 10.6+, set `utf8mb4` collation,
 pin versions before upgrades.
@@ -26,6 +28,7 @@ pin versions before upgrades.
 ---
 
 ### RQ-002 — CalDAV server: Radicale vs Baikal — SUPERSEDED
+
 Both dropped. The shared calendar now lives on **Fastmail**, not a self-hosted CalDAV server.
 Rationale: the Fastmail Android app cannot display a self-hosted CalDAV calendar, so Baikal gave the
 primary (Android/Fastmail) user no native benefit — it only helped Apple members, who are equally
@@ -38,9 +41,11 @@ Original finding (retained for reversibility): if self-hosting the calendar is e
 ---
 
 ### Calendar host decision — RESOLVED
+
 Self-hosting the calendar data was evaluated and rejected. Fastmail (already paid for) hosts the
 shared family calendar. Other household members are Apple — they reach it via the PWA (default) or
 native Apple Calendar over CalDAV (optional).
 
 ### Email scope — RESOLVED
+
 Out of scope. Members keep existing mail clients unchanged.