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/strip-comments/lib/compile.js

@@ -0,0 +1,63 @@
+'use strict';
+
+const compile = (cst, options = {}) => {
+  const keepProtected = options.safe === true || options.keepProtected === true;
+  let firstSeen = false;
+
+  const walk = (node, parent) => {
+    let output = '';
+    let inner;
+    let lines;
+
+    for (const child of node.nodes) {
+      switch (child.type) {
+        case 'block':
+          if (options.first && firstSeen === true) {
+            output += walk(child, node);
+            break;
+          }
+
+          if (options.preserveNewlines === true) {
+            inner = walk(child, node);
+            lines = inner.split('\n');
+            output += '\n'.repeat(lines.length - 1);
+            break;
+          }
+
+          if (keepProtected === true && child.protected === true) {
+            output += walk(child, node);
+            break;
+          }
+
+          firstSeen = true;
+          break;
+        case 'line':
+          if (options.first && firstSeen === true) {
+            output += child.value;
+            break;
+          }
+
+          if (keepProtected === true && child.protected === true) {
+            output += child.value;
+          }
+
+          firstSeen = true;
+          break;
+        case 'open':
+        case 'close':
+        case 'text':
+        case 'newline':
+        default: {
+          output += child.value || '';
+          break;
+        }
+      }
+    }
+
+    return output;
+  };
+
+  return walk(cst);
+};
+
+module.exports = compile;