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/resolve/.claude/notes.md

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+# resolve package - session notes
+
+## Versioning
+- Manual versioning only - do NOT use `npm version`
+- Edit package.json version directly, commit with message `v{version}`, then create annotated tag
+- Changelog lives in git tag annotations, not a separate file
+- Tag format: `git tag -a v{version} -m "{changelog}"`
+
+## Code style
+- `__proto__: null` on ALL object literals (prototype pollution protection)
+- `.slice()` not `.substring()`
+- One exported function per file
+- Move nested/inner functions to module level when feasible
+- Prefer non-hoisted declarations (function declarations at module level, not expressions)
+- No mutation - copy objects instead of modifying inputs
+
+## Testing
+- `test/list-exports` is a git submodule with sparse checkout
+- Tests should cover ALL entrypoints from fixtures, not just `'.'` subpaths
+- Use `extensions: ['.js', '.json']` when testing exports resolution
+
+## exports field implementation
+- Uses `node-exports-info` for category semantics
+- Categories: pre-exports, broken, conditions, patterns, pattern-trailers, current
+- `exportsCategory` option or `engines: true` to auto-detect from consumer's engines.node
+- Self-reference resolution respects node_modules boundaries

frontend/node_modules/resolve/.claude/settings.local.json

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+{
+  "permissions": {
+    "allow": [
+      "WebFetch(domain:github.com)",
+      "WebSearch",
+      "WebFetch(domain:raw.githubusercontent.com)",
+      "WebFetch(domain:api.github.com)",
+      "WebFetch(domain:www.npmjs.com)",
+      "Bash(tree:*)",
+      "Bash(find:*)",
+      "Bash(npm view:*)",
+      "Bash(node test/resolver_sync.js:*)",
+      "Bash(xxd:*)",
+      "Bash(npm info:*)",
+      "Bash(grep:*)",
+      "Bash(npm run submodule:update:*)",
+      "Bash(git rev-parse:*)",
+      "Bash(git -C test/list-exports diff packages/tests/fixtures/resolve-2/project/test/resolver/nested_symlinks/mylib/async.js)",
+      "Bash(gh run list:*)",
+      "Bash(ls:*)",
+      "Bash(tape test/homedir.js)",
+      "Bash(tape test/default_paths.js)",
+      "Bash(tape test/mock.js)"
+    ]
+  }
+}