fix(events): audit pass — 7 correctness fixes across the events system

Backend:
- tools.py: apply UTC normalization to update_event datetime fields
  (matched create_event which already did this)
- events.py service: allow end_dt/recurrence/project_id to be cleared
  via update_event by permitting None for nullable fields
- events.py service: find_events_by_query now returns upcoming events
  first, falling back to past — prevents AI tools from mutating stale
  past events when a future match exists
- events.py service: list_events now uses overlap logic (start <= to
  AND end >= from) so multi-day events spanning the query boundary
  are included; previously only start_dt was checked

Frontend:
- ToolCallCard: fire fable:calendar-changed on created/updated/deleted
  so CalendarView refetches without requiring a manual page refresh
- KnowledgeView: replace raw apiGet('/api/events') with listEvents()
  client function; also fix today bar which was reading .events off a
  flat array (always empty) — now correctly receives EventEntry[]
- HomeView: use full ISO strings for event date range instead of naive
  UTC-midnight strings; deduplicate inline date math via _dateRange()

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

frontend/src/components/ToolCallCard.vue

@@ -270,8 +270,11 @@ async function openEventSlideOver(id: number | undefined) {
   }
 }
 
-function closeEventSlideOver() {
+function closeEventSlideOver(changed = false) {
   eventSlideOverOpen.value = false;
+  if (changed) {
+    document.dispatchEvent(new Event("fable:calendar-changed"));
+  }
 }
 </script>
 
@@ -522,9 +525,9 @@ function closeEventSlideOver() {
     :event="eventSlideOverEntry"
     initial-date=""
     @close="closeEventSlideOver"
-    @created="closeEventSlideOver"
-    @updated="closeEventSlideOver"
-    @deleted="closeEventSlideOver"
+    @created="() => closeEventSlideOver(true)"
+    @updated="() => closeEventSlideOver(true)"
+    @deleted="() => closeEventSlideOver(true)"
   />
 </template>
 

frontend/src/views/HomeView.vue

@@ -77,9 +77,11 @@ function _dateRange() {
   const today = new Date()
   const nextWeek = new Date(today)
   nextWeek.setDate(today.getDate() + 7)
+  // Use full ISO strings so the server sees the correct UTC equivalent of
+  // local midnight / end-of-day rather than a naive UTC-midnight guess.
   return {
-    todayStr: today.toISOString().slice(0, 10) + 'T00:00:00',
-    nextWeekStr: nextWeek.toISOString().slice(0, 10) + 'T23:59:59',
+    todayStr: today.toISOString(),
+    nextWeekStr: nextWeek.toISOString(),
   }
 }
 
@@ -108,11 +110,7 @@ function _backgroundRefresh() {
 
 onMounted(async () => {
   // Phase 1: projects list + cross-project recent items + orphaned items + events — all parallel
-  const today = new Date();
-  const todayStr = today.toISOString().slice(0, 10) + "T00:00:00";
-  const nextWeek = new Date(today);
-  nextWeek.setDate(today.getDate() + 7);
-  const nextWeekStr = nextWeek.toISOString().slice(0, 10) + "T23:59:59";
+  const { todayStr, nextWeekStr } = _dateRange();
 
   const [projectsRes, recentRes, orphanTasksRes, orphanNotesRes, eventsRes] =
     await Promise.allSettled([

frontend/src/views/KnowledgeView.vue

@@ -1,7 +1,7 @@
 <script setup lang="ts">
 import { ref, computed, watch, onMounted, onUnmounted, nextTick } from "vue";
 import { useRouter } from "vue-router";
-import { apiGet, apiPatch } from "@/api/client";
+import { apiGet, apiPatch, listEvents } from "@/api/client";
 import { fmtCompact } from "@/utils/dateFormat";
 import { useChatStore } from "@/stores/chat";
 import GraphView from "@/views/GraphView.vue";
@@ -167,15 +167,13 @@ async function fetchTodayBar() {
   try {
     const now = new Date();
     const end = new Date(now.getTime() + 7 * 86_400_000);
-    const [evData, taskData] = await Promise.all([
-      apiGet<{ events: UpcomingEvent[] }>(
-        `/api/events?from=${now.toISOString().slice(0, 10)}&to=${end.toISOString().slice(0, 10)}`
-      ).catch(() => ({ events: [] as UpcomingEvent[] })),
+    const [events, taskData] = await Promise.all([
+      listEvents(now.toISOString(), end.toISOString()).catch(() => [] as UpcomingEvent[]),
       apiGet<{ total: number }>(
         `/api/tasks?status=todo&status=in_progress&overdue=true&limit=1`
       ).catch(() => ({ total: 0 })),
     ]);
-    upcomingEvents.value = (evData.events ?? []).slice(0, 3);
+    upcomingEvents.value = events.slice(0, 3);
     overdueCount.value = taskData.total ?? 0;
   } catch { /* silent */ }
 }