fix(frontend): exclude playwright/ from Jest test discovery

CI's Test Frontend job has been red since the first Playwright spec
landed. Jest's default testMatch picks up '**/*.spec.ts' which includes
playwright/specs/**/*.spec.ts; those import @playwright/test, which
can't load in the jsdom env Jest runs in:

  TypeError: Class extends value undefined is not a constructor or null
    at node_modules/playwright-core/lib/utilsBundle.js:83612:15

Local jest runs happened to pick a smaller --testPathPattern so the
breakage went unnoticed until the recent commits made both spec files
visible to the CI scan at once.

Add '<rootDir>/playwright/' alongside the existing cypress/ entry in
testPathIgnorePatterns.

Confirmed locally: jest --listTests returns zero playwright matches;
full suite 222/222 green.

Author: hans-crypto

frontend/jest.config.js

@@ -1,7 +1,10 @@
 module.exports = {
   preset: 'jest-preset-angular',
   // testMatch: ['**/*.jest.ts'],
-  testPathIgnorePatterns: ['<rootDir>/cypress/'],
+  // playwright/ is excluded so Jest doesn't try to run our browser specs
+  // (they import @playwright/test which can't load in the jsdom env and
+  // explodes with "Class extends value undefined" out of playwright-core).
+  testPathIgnorePatterns: ['<rootDir>/cypress/', '<rootDir>/playwright/'],
   setupFilesAfterEnv: ['<rootDir>/setup-jest.ts'],
   maxWorkers: 1,
   // Path aliases from tsconfig.app.json -- Jest doesn't read them automatically.