feat: SQLite persistence, non-blocking inference, modular frontend

Backend:
- Persist alert events and robot delivery counters in SQLite (data/app.db,
  YOLO_DB_PATH override); EventStore keeps its interface, DeliveryStatsStore
  uses read/write-through UPSERT; in-memory fallback remains for standalone
  AlertManager use
- Serve /api/detect from a sync endpoint and serialize YOLO inference with a
  lock, so concurrent requests no longer block the event loop
- Unify single-image and session detection: requests without session_id
  share the fixed single-image session and run full frame confirmation
- Store UTC Z-suffixed timestamps for sortable string comparison; close
  executor and database on shutdown via FastAPI lifespan

Frontend:
- Split app.js into ES modules (main.js + modules/{dom,api,ui,charts,store}
  + views/{dashboard,inspection,events,robots,robotCards}), no build step
- Escape all server data interpolated into innerHTML; guard missing
  event.classes; replace lazy element ID list with memoized qs()
- Remove hardcoded fake stats (trend badge, device donut segment)

Docs:
- Rewrite README: accurate weight policy (only trained best.pt committed,
  no Git LFS), SQLite persistence, single-worker note, data asset inventory
- Align models/pretrained/README.md with actual files; add YOLO_DB_PATH to
  .env.example; add persistence unit tests; ruff clean

frontend/views/events.js

@@ -0,0 +1,77 @@
+import { qs, escapeHtml, STATUS_LABELS, classLabel, formatDate, enabledChannelNames } from "../modules/dom.js";
+import { apiFetch } from "../modules/api.js";
+import { showToast, setServiceStatus } from "../modules/ui.js";
+import { renderTrend } from "../modules/charts.js";
+import { store } from "../modules/store.js";
+import { loadDashboard } from "./dashboard.js";
+
+let eventFilter = "";
+
+export async function loadEvents() {
+  try {
+    const query = eventFilter ? `?status=${eventFilter}` : "";
+    const result = await apiFetch(`/api/events${query}`);
+    store.eventData = result.events || [];
+    renderEventTable(store.eventData);
+    updateEventSummary(result.summary);
+    renderTrend(store.eventData);
+    setServiceStatus(true);
+  } catch (error) {
+    setServiceStatus(false);
+    showToast(`无法读取告警事件：${error.message}`, "error");
+  }
+}
+
+function updateEventSummary(summary) {
+  qs("#allEventsCount").textContent = String(summary.total);
+  qs("#pendingEventsCount").textContent = String(summary.pending);
+  qs("#ackEventsCount").textContent = String(summary.acknowledged);
+  qs("#resolvedEventsCount").textContent = String(summary.resolved);
+  qs("#pendingNavCount").textContent = String(summary.pending);
+  qs("#notificationDot").hidden = summary.pending === 0;
+}
+
+function renderEventTable(events) {
+  qs("#eventTableMeta").textContent = `${events.length} 条记录`;
+  if (!events.length) {
+    qs("#eventTableBody").innerHTML = '<tr><td colspan="7" class="empty-cell">当前筛选条件下暂无告警事件</td></tr>';
+    return;
+  }
+  qs("#eventTableBody").innerHTML = events.map((event) => {
+    const classes = (event.classes || [])
+      .map((name) => `<span class="type-tag type-${escapeHtml(name)}">${classLabel(name)}</span>`)
+      .join(" ");
+    const channels = enabledChannelNames(event.notification_channels).join(" + ") || "未发送";
+    const statusLabel = STATUS_LABELS[event.status] || escapeHtml(event.status);
+    return `<tr><td>${escapeHtml(event.id)}</td><td>${formatDate(event.created_at)}</td><td>${classes}</td><td>${Math.round(event.max_confidence * 100)}%</td><td>${channels}</td><td><span class="event-status status-${escapeHtml(event.status)}">${statusLabel}</span></td><td><div class="table-actions">${event.status === "pending" ? `<button class="table-action" data-event-id="${escapeHtml(event.id)}" data-event-status="acknowledged">确认</button>` : ""}${event.status !== "resolved" ? `<button class="table-action" data-event-id="${escapeHtml(event.id)}" data-event-status="resolved">解决</button>` : ""}</div></td></tr>`;
+  }).join("");
+}
+
+export async function updateEventStatus(eventId, status) {
+  try {
+    await apiFetch(`/api/events/${encodeURIComponent(eventId)}`, {
+      method: "PATCH",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ status }),
+    });
+    showToast(`事件 ${eventId} 已更新为${STATUS_LABELS[status]}`, "success");
+    await Promise.all([loadEvents(), loadDashboard()]);
+  } catch (error) {
+    showToast(`事件更新失败：${error.message}`, "error");
+  }
+}
+
+export function initEvents() {
+  qs("#refreshEventsButton").addEventListener("click", loadEvents);
+  qs("#eventTableBody").addEventListener("click", (event) => {
+    const button = event.target.closest("[data-event-id]");
+    if (button) updateEventStatus(button.dataset.eventId, button.dataset.eventStatus);
+  });
+  document.querySelectorAll("[data-event-filter]").forEach((button) => {
+    button.addEventListener("click", () => {
+      eventFilter = button.dataset.eventFilter;
+      document.querySelectorAll("[data-event-filter]").forEach((item) => item.classList.toggle("is-active", item === button));
+      loadEvents();
+    });
+  });
+}