Implement comprehensive frontend integration testing with Playwright

- Add Playwright E2E testing framework with cross-browser support (Chrome, Firefox)
- Create authentication helpers for CalDAV server integration
- Implement calendar interaction helpers with event creation, drag-and-drop, and view switching
- Add comprehensive drag-and-drop test suite with event cleanup
- Configure CI/CD integration with Gitea Actions for headless testing
- Support both local development and CI environments with proper dependency management
- Include video recording, screenshots, and HTML reporting for test debugging
- Handle Firefox-specific timing and interaction challenges with force clicks and timeouts

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

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

frontend/e2e/node_modules/playwright/lib/fsWatcher.js

@@ -0,0 +1,67 @@
+"use strict";
+var __defProp = Object.defineProperty;
+var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
+var __getOwnPropNames = Object.getOwnPropertyNames;
+var __hasOwnProp = Object.prototype.hasOwnProperty;
+var __export = (target, all) => {
+  for (var name in all)
+    __defProp(target, name, { get: all[name], enumerable: true });
+};
+var __copyProps = (to, from, except, desc) => {
+  if (from && typeof from === "object" || typeof from === "function") {
+    for (let key of __getOwnPropNames(from))
+      if (!__hasOwnProp.call(to, key) && key !== except)
+        __defProp(to, key, { get: () => from[key], enumerable: !(desc = __getOwnPropDesc(from, key)) || desc.enumerable });
+  }
+  return to;
+};
+var __toCommonJS = (mod) => __copyProps(__defProp({}, "__esModule", { value: true }), mod);
+var fsWatcher_exports = {};
+__export(fsWatcher_exports, {
+  Watcher: () => Watcher
+});
+module.exports = __toCommonJS(fsWatcher_exports);
+var import_utilsBundle = require("./utilsBundle");
+class Watcher {
+  constructor(onChange) {
+    this._watchedPaths = [];
+    this._ignoredFolders = [];
+    this._collector = [];
+    this._onChange = onChange;
+  }
+  async update(watchedPaths, ignoredFolders, reportPending) {
+    if (JSON.stringify([this._watchedPaths, this._ignoredFolders]) === JSON.stringify([watchedPaths, ignoredFolders]))
+      return;
+    if (reportPending)
+      this._reportEventsIfAny();
+    this._watchedPaths = watchedPaths;
+    this._ignoredFolders = ignoredFolders;
+    void this._fsWatcher?.close();
+    this._fsWatcher = void 0;
+    this._collector.length = 0;
+    clearTimeout(this._throttleTimer);
+    this._throttleTimer = void 0;
+    if (!this._watchedPaths.length)
+      return;
+    const ignored = [...this._ignoredFolders, "**/node_modules/**"];
+    this._fsWatcher = import_utilsBundle.chokidar.watch(watchedPaths, { ignoreInitial: true, ignored }).on("all", async (event, file) => {
+      if (this._throttleTimer)
+        clearTimeout(this._throttleTimer);
+      this._collector.push({ event, file });
+      this._throttleTimer = setTimeout(() => this._reportEventsIfAny(), 250);
+    });
+    await new Promise((resolve, reject) => this._fsWatcher.once("ready", resolve).once("error", reject));
+  }
+  async close() {
+    await this._fsWatcher?.close();
+  }
+  _reportEventsIfAny() {
+    if (this._collector.length)
+      this._onChange(this._collector.slice());
+    this._collector.length = 0;
+  }
+}
+// Annotate the CommonJS export names for ESM import in node:
+0 && (module.exports = {
+  Watcher
+});