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/lucide-react/dist/esm/icons/folder-git.mjs.map

@@ -0,0 +1 @@
+{"version":3,"file":"folder-git.mjs","sources":["../../../src/icons/folder-git.ts"],"sourcesContent":["import createLucideIcon from '../createLucideIcon';\nimport { IconNode } from '../types';\n\nexport const __iconNode: IconNode = [\n  ['circle', { cx: '12', cy: '13', r: '2', key: '1c1ljs' }],\n  [\n    'path',\n    {\n      d: 'M20 20a2 2 0 0 0 2-2V8a2 2 0 0 0-2-2h-7.9a2 2 0 0 1-1.69-.9L9.6 3.9A2 2 0 0 0 7.93 3H4a2 2 0 0 0-2 2v13a2 2 0 0 0 2 2Z',\n      key: '1kt360',\n    },\n  ],\n  ['path', { d: 'M14 13h3', key: '1dgedf' }],\n  ['path', { d: 'M7 13h3', key: '1pygq7' }],\n];\n\n/**\n * @component @name FolderGit\n * @description Lucide SVG icon component, renders SVG Element with children.\n *\n * @preview ![img](data:image/svg+xml;base64,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) - https://lucide.dev/icons/folder-git\n * @see https://lucide.dev/guide/packages/lucide-react - Documentation\n *\n * @param {Object} props - Lucide icons props and any valid SVG attribute\n * @returns {JSX.Element} JSX Element\n *\n */\nconst FolderGit = createLucideIcon('folder-git', __iconNode);\n\nexport default FolderGit;\n"],"names":[],"mappings":";;;;;;;;;AAGO,CAAA,CAAA,CAAA,CAAA,CAAA,CAAM,UAAA,CAAA,CAAA,CAAuB;AAAA,CAAA,CAClC,CAAC,QAAA,CAAA,CAAU,CAAA,CAAE,EAAA,CAAA,CAAI,CAAA,CAAA,CAAA,CAAA,EAAM,CAAA,CAAA,CAAA,CAAI,IAAA,CAAA,CAAM,CAAA,EAAG,CAAA,CAAA,CAAA,CAAA,CAAK,GAAA,CAAA,CAAK,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,EAAU,CAAA;AAAA,CAAA,CACxD;AAAA,CAAA,CAAA,CAAA,CACE,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA;AAAA,CAAA,CAAA,CAAA,CACA;AAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CACE,CAAA,EAAG,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA;AAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CACH,GAAA,CAAA,CAAK,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA;AAAA,CAAA,CAAA,CAAA,CAAA;AACP,CAAA,CAAA,CACF;AAAA,CAAA,CACA,CAAC,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAQ,CAAA,CAAE,GAAG,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAY,CAAA,CAAA,CAAA,CAAA,CAAK,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,GAAU,CAAA;AAAA,CAAA,CACzC,CAAC,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAQ,CAAA,CAAE,GAAG,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAW,CAAA,CAAA,CAAA,CAAA,CAAK,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,GAAU;AAC1C,CAAA;AAaA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAM,SAAA,CAAA,CAAA,CAAY,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAiB,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,EAAc,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAA,CAAU,CAAA;;"}