test: migrate e2e to Playwright and component test to Vitest browser mode

Replace Cypress with Playwright for the end-to-end suite and drop
@shellygo/cypress-test-utils in favour of a hand-written MaputnikDriver
page object that keeps the fluent then(...).shouldX() assertion style
(now async). The InputAutocomplete component test moves to Vitest browser
mode using the Playwright provider.

- e2e/maputnik-driver.ts: driver + MaputnikAssertable over Playwright
- e2e/{fixtures,coverage,global-setup,global-teardown}.ts: test fixture,
  istanbul coverage collection, and nyc report generation
- playwright.config.ts / vitest.config.ts
- Code coverage preserved: dev server is istanbul-instrumented, per-test
  window.__coverage__ is merged via nyc into coverage/coverage-final.json
- CI: Cypress jobs replaced with Playwright; docker e2e runs against the
  container via E2E_NO_WEBSERVER
- Remove Cypress deps, config and support files; update docs and .nycrc

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package.json

@@ -11,10 +11,10 @@
     "build-linux": "tsc && vite build --mode=desktop && cd desktop && make bin/linux/maputnik",
     "i18n:extract": "npx i18next-cli extract",
     "lint": "eslint",
-    "test": "cypress run",
+    "test": "playwright test",
+    "test-e2e": "playwright test",
     "test-unit": "vitest",
     "test-unit-ci": "vitest run --coverage --reporter=json",
-    "cy:open": "cypress open",
     "lint-css": "stylelint \"src/styles/*.scss\"",
     "sort-styles": "jq 'sort_by(.id)' src/config/styles.json > tmp.json && mv tmp.json src/config/styles.json"
   },
@@ -98,10 +98,9 @@
     }
   },
   "devDependencies": {
-    "@cypress/code-coverage": "^4.0.3",
     "@eslint/js": "^10.0.1",
     "@istanbuljs/nyc-config-typescript": "^1.0.2",
-    "@shellygo/cypress-test-utils": "^6.0.6",
+    "@playwright/test": "^1.61.1",
     "@stylistic/eslint-plugin": "^5.10.0",
     "@types/codemirror": "^5.60.17",
     "@types/color": "^4.2.1",
@@ -125,10 +124,10 @@
     "@types/string-hash": "^1.1.3",
     "@types/wicg-file-system-access": "^2023.10.7",
     "@vitejs/plugin-react": "^5.1.4",
-    "@vitest/coverage-v8": "^4.1.9",
+    "@vitest/browser": "^4.1.10",
+    "@vitest/browser-playwright": "^4.1.10",
+    "@vitest/coverage-v8": "^4.1.10",
     "cors": "^2.8.6",
-    "cypress": "^15.18.0",
-    "cypress-plugin-tab": "^2.0.0",
     "eslint": "^10.6.0",
     "eslint-plugin-react": "^7.37.5",
     "eslint-plugin-react-hooks": "^7.1.1",
@@ -136,6 +135,7 @@
     "i18next-cli": "^1.53.2",
     "istanbul": "^0.4.5",
     "istanbul-lib-coverage": "^3.2.2",
+    "nyc": "^18.0.0",
     "postcss": "^8.5.16",
     "react-hot-loader": "^4.13.1",
     "sass": "^1.101.0",
@@ -147,6 +147,7 @@
     "uuid": "^14.0.1",
     "vite": "^7.3.2",
     "vite-plugin-istanbul": "^9.0.1",
-    "vitest": "^4.1.9"
+    "vitest": "^4.1.10",
+    "vitest-browser-react": "^2.2.0"
   }
 }