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/fast-uri/test/uri-js-compatibility.test.js

@@ -0,0 +1,33 @@
+'use strict'
+
+const test = require('tape')
+const fastURI = require('../')
+
+const uriJsParseFixtures = require('./fixtures/uri-js-parse.json')
+const uriJsSerializeFixtures = require('./fixtures/uri-js-serialize.json')
+
+test('uri-js compatibility Parse', (t) => {
+  uriJsParseFixtures.forEach((
+    [value, expected]
+  ) => {
+    if (value === '//10.10.000.10') {
+      return t.skip('Skipping //10.10.000.10 as it is not a valid URI per URI spec: https://datatracker.ietf.org/doc/html/rfc5954#section-4.1')
+    }
+    if (value.slice(0, 6) === 'mailto') {
+      return t.skip('Skipping mailto schema test as it is not supported by fastifyURI')
+    }
+    t.same(JSON.parse(JSON.stringify(fastURI.parse(value))), expected, 'Compatibility parse: ' + value)
+  })
+  t.end()
+})
+
+test('uri-js compatibility serialize', (t) => {
+  uriJsSerializeFixtures.forEach(([value, expected]) => {
+    t.same(
+      fastURI.serialize(value),
+      expected,
+      'Compatibility serialize: ' + JSON.stringify(value)
+    )
+  })
+  t.end()
+})