feat(import): use WebSocket push for progress updates with polling fallback

templates/import.html

@@ -882,7 +882,7 @@ function showProgress(show, message = '', percent = null) {
 // Batch progress monitoring
 // -----------------------------
 const TERMINAL_BATCH_STATUSES = new Set(['success', 'completed_with_errors', 'failed']);
-let batchProgress = { timer: null, auditId: null };
+let batchProgress = { timer: null, auditId: null, wsMgr: null };
 
 async function fetchCurrentBatch() {
     try {
@@ -899,6 +899,8 @@ function stopBatchProgressPolling() {
         batchProgress.timer = null;
     }
     batchProgress.auditId = null;
+    try { if (batchProgress.wsMgr) { batchProgress.wsMgr.close(); } } catch (_) {}
+    batchProgress.wsMgr = null;
 }
 
 async function pollBatchProgressOnce(auditId) {
@@ -924,9 +926,48 @@ async function pollBatchProgressOnce(auditId) {
 function startBatchProgressPolling(auditId) {
     stopBatchProgressPolling();
     batchProgress.auditId = auditId;
-    // immediate + interval polling
-    pollBatchProgressOnce(auditId);
-    batchProgress.timer = setInterval(() => pollBatchProgressOnce(auditId), 1500);
+    // Try WebSocket first; fallback to polling
+    try {
+        const mgr = new (window.notifications && window.notifications.NotificationManager ? window.notifications.NotificationManager : null)({
+            getUrl: () => `/api/import/batch-progress/ws/${encodeURIComponent(auditId)}`,
+            onMessage: (msg) => {
+                if (!msg || !msg.type) return;
+                if (msg.type === 'progress') {
+                    const p = msg.data || {};
+                    const percent = Number(p.percent || 0);
+                    const total = Number(p.total_files || 0);
+                    const processed = Number(p.processed_files || 0);
+                    const status = String(p.status || 'running');
+                    const statusNice = status.replaceAll('_', ' ');
+                    const msgText = total > 0
+                        ? `Processing ${processed}/${total} (${percent.toFixed(1)}%) · ${statusNice}`
+                        : `Processing… ${statusNice}`;
+                    showProgress(true, msgText, percent);
+                    if (TERMINAL_BATCH_STATUSES.has(status)) {
+                        stopBatchProgressPolling();
+                    }
+                }
+            },
+            onStateChange: (state) => {
+                if (state === 'error' || state === 'closed' || state === 'offline') {
+                    // fallback to polling
+                    if (!batchProgress.timer) {
+                        pollBatchProgressOnce(auditId);
+                        batchProgress.timer = setInterval(() => pollBatchProgressOnce(auditId), 1500);
+                    }
+                }
+            },
+            autoConnect: true,
+            debug: false
+        });
+        batchProgress.wsMgr = mgr;
+        // Safety: also do an immediate HTTP fetch as first snapshot
+        pollBatchProgressOnce(auditId);
+    } catch (_) {
+        // immediate + interval polling
+        pollBatchProgressOnce(auditId);
+        batchProgress.timer = setInterval(() => pollBatchProgressOnce(auditId), 1500);
+    }
 }
 
 async function ensureAuditIdWithRetry(maxAttempts = 10, delayMs = 500) {