Add sync error logging, extend error flash, fix unload saves

- Log workforce sync errors to backend stdout so they appear in docker logs
- Extend error flash from 5s to 15s so errors are readable
- Replace sendBeacon (POST-only) with keepalive fetch (PUT) on unload —
  sendBeacon was hitting 404s on all three unload saves

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

frontend/node_modules/ajv/dist/compile/validate/applicability.js

@@ -0,0 +1,19 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.shouldUseRule = exports.shouldUseGroup = exports.schemaHasRulesForType = void 0;
+function schemaHasRulesForType({ schema, self }, type) {
+    const group = self.RULES.types[type];
+    return group && group !== true && shouldUseGroup(schema, group);
+}
+exports.schemaHasRulesForType = schemaHasRulesForType;
+function shouldUseGroup(schema, group) {
+    return group.rules.some((rule) => shouldUseRule(schema, rule));
+}
+exports.shouldUseGroup = shouldUseGroup;
+function shouldUseRule(schema, rule) {
+    var _a;
+    return (schema[rule.keyword] !== undefined ||
+        ((_a = rule.definition.implements) === null || _a === void 0 ? void 0 : _a.some((kwd) => schema[kwd] !== undefined)));
+}
+exports.shouldUseRule = shouldUseRule;
+//# sourceMappingURL=applicability.js.map