Make biz compare async and cutover-friendly for large tables.

Run compares in the background with progress, persist fails first, and store success as sampled key+row_id hydrated from source so million-row sheets no longer block the API.

Co-authored-by: Cursor <cursoragent@cursor.com>

web/src/i18n/en.ts

@@ -494,6 +494,22 @@ const en = {
     needBeforeBatch: "Select before task and batch",
     needAfterBatch: "Select after batch",
     runNow: "Run now",
+    runStarted: "Compare started in background — you can close this page; check run history for progress",
+    runFailed: "Compare failed",
+    runStatusRunning: "Running",
+    runStatusFailed: "Failed",
+    runStatusDoneSec: "Done {{s}}s",
+    runProgress: "{{phase}} · sheet {{i}}/{{n}} · {{sheet}} · {{s}}s elapsed",
+    ranWithDuration: "Compare finished ({{s}}s)",
+    unchangedNotStored: "Success rows were counted but not stored. Set “Store success rows” to sample and re-run for spot-check.",
+    unchangedSampleHint: "{{total}} success rows total; browsing a sample of {{listed}} (hydrated from source tables for cutover spot-check). Pass rate uses all {{total}}.",
+    storeUnchanged: "Store success rows",
+    storeUnchangedAuto: "Auto (full if small / sample 5k + hydrate if large)",
+    storeUnchangedSample: "Sample only (up to 5k keys + hydrate)",
+    storeUnchangedKeys: "All success keys (full browse; large write still slow)",
+    storeUnchangedAlways: "Always full JSON (slow on huge sheets)",
+    storeUnchangedNever: "Never (counts only)",
+    storeUnchangedHint: "Cutover focuses on fails and pass rate; success defaults to a sample. Pass rate always uses the full success count.",
     saveJob: "Save config",
     jobSaved: "Job config saved",
     jobDeleted: "Compare job deleted",