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/workbox-routing/src/Route.ts

@@ -0,0 +1,80 @@
+/*
+  Copyright 2018 Google LLC
+
+  Use of this source code is governed by an MIT-style
+  license that can be found in the LICENSE file or at
+  https://opensource.org/licenses/MIT.
+*/
+
+import {assert} from 'workbox-core/_private/assert.js';
+import {HTTPMethod, defaultMethod, validMethods} from './utils/constants.js';
+import {normalizeHandler} from './utils/normalizeHandler.js';
+import {
+  RouteHandler,
+  RouteHandlerObject,
+  RouteMatchCallback,
+} from 'workbox-core/types.js';
+import './_version.js';
+
+/**
+ * A `Route` consists of a pair of callback functions, "match" and "handler".
+ * The "match" callback determine if a route should be used to "handle" a
+ * request by returning a non-falsy value if it can. The "handler" callback
+ * is called when there is a match and should return a Promise that resolves
+ * to a `Response`.
+ *
+ * @memberof workbox-routing
+ */
+class Route {
+  handler: RouteHandlerObject;
+  match: RouteMatchCallback;
+  method: HTTPMethod;
+  catchHandler?: RouteHandlerObject;
+
+  /**
+   * Constructor for Route class.
+   *
+   * @param {workbox-routing~matchCallback} match
+   * A callback function that determines whether the route matches a given
+   * `fetch` event by returning a non-falsy value.
+   * @param {workbox-routing~handlerCallback} handler A callback
+   * function that returns a Promise resolving to a Response.
+   * @param {string} [method='GET'] The HTTP method to match the Route
+   * against.
+   */
+  constructor(
+    match: RouteMatchCallback,
+    handler: RouteHandler,
+    method: HTTPMethod = defaultMethod,
+  ) {
+    if (process.env.NODE_ENV !== 'production') {
+      assert!.isType(match, 'function', {
+        moduleName: 'workbox-routing',
+        className: 'Route',
+        funcName: 'constructor',
+        paramName: 'match',
+      });
+
+      if (method) {
+        assert!.isOneOf(method, validMethods, {paramName: 'method'});
+      }
+    }
+
+    // These values are referenced directly by Router so cannot be
+    // altered by minificaton.
+    this.handler = normalizeHandler(handler);
+    this.match = match;
+    this.method = method;
+  }
+
+  /**
+   *
+   * @param {workbox-routing-handlerCallback} handler A callback
+   * function that returns a Promise resolving to a Response
+   */
+  setCatchHandler(handler: RouteHandler): void {
+    this.catchHandler = normalizeHandler(handler);
+  }
+}
+
+export {Route};