test: add jest test suite with controller specs and mocks

- add jest, ts-jest, supertest, and related dev dependencies
- add test scripts (test, test:debug, test:watch) to package.json
- add jest.config.js with ts-jest transform and module name mappers
- add controller specs for auth, browser, environment, mcp, scenario, session
- add mocks for jsdom, playwright, and readability
- add test/tsconfig.json and exclude test dir from main tsconfig

jest.config.js

@@ -0,0 +1,15 @@
+/** @type {import('jest').Config} */
+module.exports = {
+  moduleFileExtensions: ['js', 'json', 'ts'],
+  rootDir: '.',
+  testRegex: 'test/.*\\.spec\\.ts$',
+  transform: {
+    '^.+\\.ts$': ['ts-jest', { tsconfig: 'test/tsconfig.json' }],
+  },
+  moduleNameMapper: {
+    '^jsdom$': '<rootDir>/test/__mocks__/jsdom.ts',
+    '^playwright$': '<rootDir>/test/__mocks__/playwright.ts',
+    '^@mozilla/readability$': '<rootDir>/test/__mocks__/readability.ts',
+  },
+  testEnvironment: 'node',
+};