feat(03-11): GREEN — re-read freshest calendarEvents etag before update PUT (WR-02)

- In update dispatch, SELECT etag FROM calendar_events WHERE uid = row.uid before PUT
- Use fresh etag as If-Match instead of stale enqueue-time row.etag when available
- Fall back to row.etag when calendarEvents has no matching row
- D-08 conflict detection intact: genuine external changes update calendarEvents.etag
  differently from any pending row, so they still 412 correctly

apps/api/src/broker/outboxWorker.ts

@@ -193,11 +193,28 @@ async function dispatchRow(row: OutboxRow): Promise<DispatchResult> {
       description: fields.description as string | undefined,
       rruleString: fields.recurrence && fields.recurrence !== 'none' ? RRULE_PRESETS[fields.recurrence as string] : undefined,
     })
+    // WR-02: re-read the freshest etag from calendarEvents just before PUT.
+    // Rapid successive edits to the same uid enqueue multiple update rows, each
+    // carrying the etag at enqueue time. If a prior edit succeeded and triggered
+    // a re-sync, calendarEvents.etag was updated but the next update row still
+    // carries the old enqueue-time etag — guaranteed 412 on the second edit.
+    // Using the freshest cached etag here prevents the spurious conflict toast
+    // while still preserving genuine conflict detection (D-08): a real external
+    // change updates calendarEvents.etag differently from any pending row's etag.
+    let etagForPut: string | null = row.etag ?? null
+    const freshEtagRows = (await db
+      .select({ etag: calendarEvents.etag })
+      .from(calendarEvents)
+      .where(eq(calendarEvents.uid, row.uid))) as Array<{ etag: string | null }>
+    if (freshEtagRows.length > 0 && freshEtagRows[0].etag != null) {
+      etagForPut = freshEtagRows[0].etag
+    }
+
     response = await updateCalendarEvent(
       client,
       row.calendarObjectUrl,
       icsString,
-      row.etag ?? null,
+      etagForPut,
     )
   } else {
     // create