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/regjsparser/package.json

@@ -0,0 +1,47 @@
+{
+  "name": "regjsparser",
+  "version": "0.13.2",
+  "author": "'Julian Viereck' <julian.viereck@gmail.com>",
+  "license": "BSD-2-Clause",
+  "main": "./parser",
+  "types": "./parser.d.ts",
+  "bin": {
+    "regjsparser": "bin/parser"
+  },
+  "homepage": "https://github.com/jviereck/regjsparser",
+  "repository": {
+    "type": "git",
+    "url": "git+ssh://git@github.com/jviereck/regjsparser.git"
+  },
+  "scripts": {
+    "lint": "eslint --max-warnings 0 .",
+    "test": "run-p test:* lint",
+    "test:src": "node test/index.js",
+    "test:types": "tsc test/types.ts --noEmit",
+    "bench:baseline": "node ./tools/bench/index.mjs baseline",
+    "bench:current": "node ./tools/bench/index.mjs current",
+    "bench": "run-s bench:*"
+  },
+  "files": [
+    "bin/",
+    "LICENSE.BSD",
+    "parser.js",
+    "parser.d.ts",
+    "README.md"
+  ],
+  "dependencies": {
+    "jsesc": "~3.1.0"
+  },
+  "devDependencies": {
+    "@eslint/js": "^10.0.1",
+    "@unicode/unicode-17.0.0": "^1.6.12",
+    "eslint": "^10.0.2",
+    "eslint-plugin-regexp": "^3.0.0",
+    "globals": "^17.3.0",
+    "npm-run-all": "^4.1.5",
+    "regenerate": "^1.4.2",
+    "regjsparser": "^0.11.2",
+    "tinybench": "^5.0.1",
+    "typescript": "~5.9.2"
+  }
+}