feat(11-02): Task 3 — all-day 9 AM-local fire branch + dedup prune fix (NOTIF-06)

- Add all-day 9 AM tests: 0-lead fires at EDT alert UTC, not midnight
- Add 1440-lead (day-before) and 10080-lead (7-day-before) tests
- Add all-day dedup test: same uid:dtstartMs fires once across ticks
- Fix all-day prune bug: store start-of-next-day as pruneMs instead of
  UTC midnight (which was always <= now by fire time, causing immediate prune)
- Separate dtstartMs (dedup key component) from pruneMs (map cleanup value)
- 28/28 tests GREEN; full API suite 314/314; tsc --noEmit clean

apps/api/src/broker/reminderScheduler.ts

@@ -183,7 +183,8 @@ export async function runReminderCheck(now = new Date()): Promise<void> {
     {
       uid: string;
       title: string | null;
-      dtstartMs: number;
+      dtstartMs: number;  // key component — used for compound dedup key
+      pruneMs: number;    // when to prune: dtstartUtc for timed; end-of-event-date for all-day
       reminderLeadMinutes: number;
       dateStr: string;
       subs: SubRow[];
@@ -211,6 +212,7 @@ export async function runReminderCheck(now = new Date()): Promise<void> {
         uid: row.uid,
         title: row.title ?? null,
         dtstartMs,
+        pruneMs: dtstartMs, // timed: prune when event has started (dtstartUtc <= now)
         reminderLeadMinutes: lead,
         dateStr: yyyyMmDd(dtstartUtc),
         subs: [],
@@ -248,11 +250,17 @@ export async function runReminderCheck(now = new Date()): Promise<void> {
     const dtstartMs = Date.UTC(y, m - 1, d); // UTC midnight of event date
     const dedupKey = `${row.uid}:${dtstartMs}`;
 
+    // Prune value for all-day events: start-of-next-day UTC.
+    // Using UTC midnight of dtstartDate would be pruned immediately (it's in the past by 9 AM);
+    // using end-of-event-day ensures the entry persists through the full fire window.
+    const pruneMs = Date.UTC(y, m - 1, d + 1); // UTC midnight of event date + 1 day
+
     if (!byKey.has(dedupKey)) {
       byKey.set(dedupKey, {
         uid: row.uid,
         title: row.title ?? null,
         dtstartMs,
+        pruneMs,
         reminderLeadMinutes: lead,
         dateStr: dtstartDate,
         subs: [],
@@ -302,7 +310,10 @@ export async function runReminderCheck(now = new Date()): Promise<void> {
       // WR-01: mark sent AFTER all dispatches have been attempted. Pre-marking before
       // dispatch prevents retry when dispatchPush throws — at-least-once delivery
       // requires not pre-marking.
-      sentReminders.set(dedupKey, event.dtstartMs);
+      // Store pruneMs (not dtstartMs) so the CR-01 prune removes the entry at the right time:
+      // - timed: pruneMs = dtstartUtc → pruned when event starts
+      // - all-day: pruneMs = start-of-next-day → pruned after the event date
+      sentReminders.set(dedupKey, event.pruneMs);
     } catch (err) {
       // Per-event error isolation (T-05-18): one bad event never aborts remaining events.
       console.error(