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/@babel/plugin-transform-react-jsx-source/lib/index.js

@@ -0,0 +1,51 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+var _helperPluginUtils = require("@babel/helper-plugin-utils");
+var _core = require("@babel/core");
+const TRACE_ID = "__source";
+const FILE_NAME_VAR = "_jsxFileName";
+const createNodeFromNullish = (val, fn) => val == null ? _core.types.nullLiteral() : fn(val);
+var _default = exports.default = (0, _helperPluginUtils.declare)(api => {
+  api.assertVersion(7);
+  function makeTrace(fileNameIdentifier, {
+    line,
+    column
+  }) {
+    const fileLineLiteral = createNodeFromNullish(line, _core.types.numericLiteral);
+    const fileColumnLiteral = createNodeFromNullish(column, c => _core.types.numericLiteral(c + 1));
+    return _core.template.expression.ast`{
+      fileName: ${fileNameIdentifier},
+      lineNumber: ${fileLineLiteral},
+      columnNumber: ${fileColumnLiteral},
+    }`;
+  }
+  const isSourceAttr = attr => _core.types.isJSXAttribute(attr) && attr.name.name === TRACE_ID;
+  return {
+    name: "transform-react-jsx-source",
+    visitor: {
+      JSXOpeningElement(path, state) {
+        const {
+          node
+        } = path;
+        if (!node.loc || path.node.attributes.some(isSourceAttr)) {
+          return;
+        }
+        if (!state.fileNameIdentifier) {
+          const fileNameId = path.scope.generateUidIdentifier(FILE_NAME_VAR);
+          state.fileNameIdentifier = fileNameId;
+          path.scope.getProgramParent().push({
+            id: fileNameId,
+            init: _core.types.stringLiteral(state.filename || "")
+          });
+        }
+        node.attributes.push(_core.types.jsxAttribute(_core.types.jsxIdentifier(TRACE_ID), _core.types.jsxExpressionContainer(makeTrace(_core.types.cloneNode(state.fileNameIdentifier), node.loc.start))));
+      }
+    }
+  };
+});
+
+//# sourceMappingURL=index.js.map