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>

vitest.config.ts

@@ -0,0 +1,37 @@
+import { defineConfig } from "vitest/config";
+import react from "@vitejs/plugin-react";
+import { playwright } from "@vitest/browser-playwright";
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    projects: [
+      {
+        extends: true,
+        test: {
+          name: "unit",
+          environment: "node",
+          include: ["src/**/*.test.{ts,tsx}"],
+          exclude: ["src/**/*.browser.test.{ts,tsx}"],
+        },
+      },
+      {
+        extends: true,
+        test: {
+          name: "browser",
+          include: ["src/**/*.browser.test.{ts,tsx}"],
+          browser: {
+            enabled: true,
+            provider: playwright(),
+            headless: true,
+            instances: [{ browser: "chromium" }],
+          },
+        },
+      },
+    ],
+    coverage: {
+      provider: "v8",
+      reporter: ["json", "lcov", "text-summary"],
+    },
+  },
+});