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/whatwg-url/lib/urlencoded.js

@@ -0,0 +1,89 @@
+"use strict";
+const { utf8Encode, utf8DecodeWithoutBOM } = require("./encoding");
+const { percentDecodeBytes, utf8PercentEncodeString, isURLEncodedPercentEncode } = require("./percent-encoding");
+
+function p(char) {
+  return char.codePointAt(0);
+}
+
+// https://url.spec.whatwg.org/#concept-urlencoded-parser
+function parseUrlencoded(input) {
+  const sequences = strictlySplitByteSequence(input, p("&"));
+  const output = [];
+  for (const bytes of sequences) {
+    if (bytes.length === 0) {
+      continue;
+    }
+
+    let name, value;
+    const indexOfEqual = bytes.indexOf(p("="));
+
+    if (indexOfEqual >= 0) {
+      name = bytes.slice(0, indexOfEqual);
+      value = bytes.slice(indexOfEqual + 1);
+    } else {
+      name = bytes;
+      value = new Uint8Array(0);
+    }
+
+    name = replaceByteInByteSequence(name, 0x2B, 0x20);
+    value = replaceByteInByteSequence(value, 0x2B, 0x20);
+
+    const nameString = utf8DecodeWithoutBOM(percentDecodeBytes(name));
+    const valueString = utf8DecodeWithoutBOM(percentDecodeBytes(value));
+
+    output.push([nameString, valueString]);
+  }
+  return output;
+}
+
+// https://url.spec.whatwg.org/#concept-urlencoded-string-parser
+function parseUrlencodedString(input) {
+  return parseUrlencoded(utf8Encode(input));
+}
+
+// https://url.spec.whatwg.org/#concept-urlencoded-serializer
+function serializeUrlencoded(tuples) {
+  // TODO: accept and use encoding argument
+
+  let output = "";
+  for (const [i, tuple] of tuples.entries()) {
+    const name = utf8PercentEncodeString(tuple[0], isURLEncodedPercentEncode, true);
+    const value = utf8PercentEncodeString(tuple[1], isURLEncodedPercentEncode, true);
+
+    if (i !== 0) {
+      output += "&";
+    }
+    output += `${name}=${value}`;
+  }
+  return output;
+}
+
+function strictlySplitByteSequence(buf, cp) {
+  const list = [];
+  let last = 0;
+  let i = buf.indexOf(cp);
+  while (i >= 0) {
+    list.push(buf.slice(last, i));
+    last = i + 1;
+    i = buf.indexOf(cp, last);
+  }
+  if (last !== buf.length) {
+    list.push(buf.slice(last));
+  }
+  return list;
+}
+
+function replaceByteInByteSequence(buf, from, to) {
+  let i = buf.indexOf(from);
+  while (i >= 0) {
+    buf[i] = to;
+    i = buf.indexOf(from, i + 1);
+  }
+  return buf;
+}
+
+module.exports = {
+  parseUrlencodedString,
+  serializeUrlencoded
+};