Set up comprehensive frontend testing infrastructure

- Install Jest for unit testing with React Testing Library
- Install Playwright for end-to-end testing
- Configure Jest with proper TypeScript support and module mapping
- Create test setup files and utilities for both unit and e2e tests

Components:
* Jest configuration with coverage thresholds
* Playwright configuration with browser automation
* Unit tests for LoginForm, AuthContext, and useSocketIO hook
* E2E tests for authentication, dashboard, and agents workflows
* GitHub Actions workflow for automated testing
* Mock data and API utilities for consistent testing
* Test documentation with best practices

Testing features:
- Unit tests with 70% coverage threshold
- E2E tests with API mocking and user journey testing
- CI/CD integration for automated test runs
- Cross-browser testing support with Playwright
- Authentication system testing end-to-end

🚀 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/node_modules/@testing-library/user-event/dist/esm/document/trackValue.js

@@ -0,0 +1,53 @@
+import '../utils/dataTransfer/Clipboard.js';
+import { getWindow } from '../utils/misc/getWindow.js';
+import { setUIValueClean, setUISelection, hasUISelection } from './UI.js';
+
+const TrackChanges = Symbol('Track programmatic changes for React workaround');
+// When the input event happens in the browser, React executes all event handlers
+// and if they change state of a controlled value, nothing happens.
+// But when we trigger the event handlers in test environment with React@17,
+// the changes are rolled back before the state update is applied.
+// This results in a reset cursor.
+// There might be a better way to work around if we figure out
+// why the batched update is executed differently in our test environment.
+function isReact17Element(element) {
+    return Object.getOwnPropertyNames(element).some((k)=>k.startsWith('__react')) && getWindow(element).REACT_VERSION === 17;
+}
+function startTrackValue(element) {
+    if (!isReact17Element(element)) {
+        return;
+    }
+    element[TrackChanges] = {
+        previousValue: String(element.value),
+        tracked: []
+    };
+}
+function trackOrSetValue(element, v) {
+    var _element_TrackChanges_tracked, _element_TrackChanges;
+    (_element_TrackChanges = element[TrackChanges]) === null || _element_TrackChanges === undefined ? undefined : (_element_TrackChanges_tracked = _element_TrackChanges.tracked) === null || _element_TrackChanges_tracked === undefined ? undefined : _element_TrackChanges_tracked.push(v);
+    if (!element[TrackChanges]) {
+        setUIValueClean(element);
+        setUISelection(element, {
+            focusOffset: v.length
+        });
+    }
+}
+function commitValueAfterInput(element, cursorOffset) {
+    var _changes_tracked;
+    const changes = element[TrackChanges];
+    element[TrackChanges] = undefined;
+    if (!(changes === null || changes === undefined ? undefined : (_changes_tracked = changes.tracked) === null || _changes_tracked === undefined ? undefined : _changes_tracked.length)) {
+        return;
+    }
+    const isJustReactStateUpdate = changes.tracked.length === 2 && changes.tracked[0] === changes.previousValue && changes.tracked[1] === element.value;
+    if (!isJustReactStateUpdate) {
+        setUIValueClean(element);
+    }
+    if (hasUISelection(element)) {
+        setUISelection(element, {
+            focusOffset: isJustReactStateUpdate ? cursorOffset : element.value.length
+        });
+    }
+}
+
+export { commitValueAfterInput, startTrackValue, trackOrSetValue };