build(web): add project-local Playwright tooling

- build: pin Playwright Test and MCP with repository-local npm, browser, and artifact paths plus sandboxed headless Chromium configuration.
- test: add a browser smoke test for the login page while keeping Playwright isolated from Vitest.
- docs: document Debian dependency setup, dual Chromium revisions, E2E commands, and project-scoped Codex MCP usage.

web/package.json

@@ -11,7 +11,11 @@
     "dev": "vite",
     "build": "tsc -b && vite build",
     "lint": "oxlint",
+    "playwright:install": "playwright install chromium",
+    "playwright:install:deps": "playwright install-deps chromium",
+    "playwright:install:mcp": "node node_modules/playwright/cli.js install chromium",
     "test": "vitest run",
+    "test:e2e": "playwright test",
     "typecheck": "tsc -b",
     "check": "npm run lint && npm run test && npm run build",
     "preview": "vite preview"
@@ -25,6 +29,8 @@
     "react-router": "^8.2.0"
   },
   "devDependencies": {
+    "@playwright/mcp": "0.0.78",
+    "@playwright/test": "1.61.1",
     "@tailwindcss/vite": "^4.3.2",
     "@types/node": "^24.13.2",
     "@types/react": "^19.2.17",