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/matchers/toEqual.js

@@ -0,0 +1,94 @@
+"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 toEqual_exports = {};
+__export(toEqual_exports, {
+  toEqual: () => toEqual
+});
+module.exports = __toCommonJS(toEqual_exports);
+var import_utils = require("playwright-core/lib/utils");
+var import_util = require("../util");
+var import_matcherHint = require("./matcherHint");
+const EXPECTED_LABEL = "Expected";
+const RECEIVED_LABEL = "Received";
+async function toEqual(matcherName, receiver, receiverType, query, expected, options = {}, messagePreventExtraStatIndent) {
+  (0, import_util.expectTypes)(receiver, [receiverType], matcherName);
+  const matcherOptions = {
+    comment: options.contains ? "" : "deep equality",
+    isNot: this.isNot,
+    promise: this.promise
+  };
+  const timeout = options.timeout ?? this.timeout;
+  const { matches: pass, received, log, timedOut } = await query(!!this.isNot, timeout);
+  if (pass === !this.isNot) {
+    return {
+      name: matcherName,
+      message: () => "",
+      pass,
+      expected
+    };
+  }
+  let printedReceived;
+  let printedExpected;
+  let printedDiff;
+  if (pass) {
+    printedExpected = `Expected: not ${this.utils.printExpected(expected)}`;
+    printedReceived = `Received: ${this.utils.printReceived(received)}`;
+  } else if (Array.isArray(expected) && Array.isArray(received)) {
+    const normalizedExpected = expected.map((exp, index) => {
+      const rec = received[index];
+      if ((0, import_utils.isRegExp)(exp))
+        return exp.test(rec) ? rec : exp;
+      return exp;
+    });
+    printedDiff = this.utils.printDiffOrStringify(
+      normalizedExpected,
+      received,
+      EXPECTED_LABEL,
+      RECEIVED_LABEL,
+      false
+    );
+  } else {
+    printedDiff = this.utils.printDiffOrStringify(
+      expected,
+      received,
+      EXPECTED_LABEL,
+      RECEIVED_LABEL,
+      false
+    );
+  }
+  const message = () => {
+    const details = printedDiff || `${printedExpected}
+${printedReceived}`;
+    const header = (0, import_matcherHint.matcherHint)(this, receiver, matcherName, "locator", void 0, matcherOptions, timedOut ? timeout : void 0, details, messagePreventExtraStatIndent);
+    return `${header}${(0, import_util.callLogText)(log)}`;
+  };
+  return {
+    actual: received,
+    expected,
+    message,
+    name: matcherName,
+    pass,
+    log,
+    timeout: timedOut ? timeout : void 0
+  };
+}
+// Annotate the CommonJS export names for ESM import in node:
+0 && (module.exports = {
+  toEqual
+});