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/cjs/document/UI.js

@@ -0,0 +1,92 @@
+'use strict';
+
+const UIValue = Symbol('Displayed value in UI');
+const UISelection = Symbol('Displayed selection in UI');
+const InitialValue = Symbol('Initial value to compare on blur');
+function isUIValue(value) {
+    return typeof value === 'object' && UIValue in value;
+}
+function isUISelectionStart(start) {
+    return !!start && typeof start === 'object' && UISelection in start;
+}
+function setUIValue(element, value) {
+    if (element[InitialValue] === undefined) {
+        element[InitialValue] = element.value;
+    }
+    element[UIValue] = value;
+    // eslint-disable-next-line no-new-wrappers
+    element.value = Object.assign(new String(value), {
+        [UIValue]: true
+    });
+}
+function getUIValue(element) {
+    return element[UIValue] === undefined ? element.value : String(element[UIValue]);
+}
+/** Flag the IDL value as clean. This does not change the value.*/ function setUIValueClean(element) {
+    element[UIValue] = undefined;
+}
+function clearInitialValue(element) {
+    element[InitialValue] = undefined;
+}
+function getInitialValue(element) {
+    return element[InitialValue];
+}
+function setUISelectionRaw(element, selection) {
+    element[UISelection] = selection;
+}
+function setUISelection(element, { focusOffset: focusOffsetParam, anchorOffset: anchorOffsetParam = focusOffsetParam }, mode = 'replace') {
+    const valueLength = getUIValue(element).length;
+    const sanitizeOffset = (o)=>Math.max(0, Math.min(valueLength, o));
+    const anchorOffset = mode === 'replace' || element[UISelection] === undefined ? sanitizeOffset(anchorOffsetParam) : element[UISelection].anchorOffset;
+    const focusOffset = sanitizeOffset(focusOffsetParam);
+    const startOffset = Math.min(anchorOffset, focusOffset);
+    const endOffset = Math.max(anchorOffset, focusOffset);
+    element[UISelection] = {
+        anchorOffset,
+        focusOffset
+    };
+    if (element.selectionStart === startOffset && element.selectionEnd === endOffset) {
+        return;
+    }
+    // eslint-disable-next-line no-new-wrappers
+    const startObj = Object.assign(new Number(startOffset), {
+        [UISelection]: true
+    });
+    try {
+        element.setSelectionRange(startObj, endOffset);
+    } catch  {
+    // DOMException for invalid state is expected when calling this
+    // on an element without support for setSelectionRange
+    }
+}
+function getUISelection(element) {
+    var _element_selectionStart, _element_selectionEnd, _element_UISelection;
+    const sel = (_element_UISelection = element[UISelection]) !== null && _element_UISelection !== undefined ? _element_UISelection : {
+        anchorOffset: (_element_selectionStart = element.selectionStart) !== null && _element_selectionStart !== undefined ? _element_selectionStart : 0,
+        focusOffset: (_element_selectionEnd = element.selectionEnd) !== null && _element_selectionEnd !== undefined ? _element_selectionEnd : 0
+    };
+    return {
+        ...sel,
+        startOffset: Math.min(sel.anchorOffset, sel.focusOffset),
+        endOffset: Math.max(sel.anchorOffset, sel.focusOffset)
+    };
+}
+function hasUISelection(element) {
+    return !!element[UISelection];
+}
+/** Flag the IDL selection as clean. This does not change the selection. */ function setUISelectionClean(element) {
+    element[UISelection] = undefined;
+}
+
+exports.clearInitialValue = clearInitialValue;
+exports.getInitialValue = getInitialValue;
+exports.getUISelection = getUISelection;
+exports.getUIValue = getUIValue;
+exports.hasUISelection = hasUISelection;
+exports.isUISelectionStart = isUISelectionStart;
+exports.isUIValue = isUIValue;
+exports.setUISelection = setUISelection;
+exports.setUISelectionClean = setUISelectionClean;
+exports.setUISelectionRaw = setUISelectionRaw;
+exports.setUIValue = setUIValue;
+exports.setUIValueClean = setUIValueClean;