Real-browser tests (Playwright) and housekeeping

- npm run test:e2e builds the app, runs it on port 3101 with an empty throwaway
  database and drives Chrome (the installed one; no browser download) through
  notes and the paste check, the daily five minutes and weekly recall,
  translation compare (Bible text faked), and two-screen presenting.
- Vitest skips e2e/; ESLint knows the e2e folder and playwright.config.js.
- .gitignore: the local demo video, Playwright output and sign-in file.
- README and TODO describe the browser tests and what CI still needs.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

package-lock.json

@@ -27,6 +27,7 @@
       },
       "devDependencies": {
         "@eslint/js": "^10.0.1",
+        "@playwright/test": "^1.64.1",
         "@testing-library/jest-dom": "^6.9.1",
         "@testing-library/react": "^16.3.2",
         "@testing-library/user-event": "^14.6.1",
@@ -1635,6 +1636,22 @@
         "node": ">=20.0.0"
       }
     },
+    "node_modules/@playwright/test": {
+      "version": "1.64.1",
+      "resolved": "https://registry.npmjs.org/@playwright/test/-/test-1.64.1.tgz",
+      "integrity": "sha512-IaYGml/nSOiZWROfPtuIL7neuu9qDOZ3TNvNljUIrhDMxiGTgPjzj/g9p9RxpS2tSepPDRY+UwAaEeiKtUvIAg==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "playwright": "1.64.1"
+      },
+      "bin": {
+        "playwright": "cli.js"
+      },
+      "engines": {
+        "node": ">=20"
+      }
+    },
     "node_modules/@rolldown/binding-android-arm64": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/@rolldown/binding-android-arm64/-/binding-android-arm64-1.0.2.tgz",
@@ -6190,6 +6207,35 @@
         "node": ">= 6"
       }
     },
+    "node_modules/playwright": {
+      "version": "1.64.1",
+      "resolved": "https://registry.npmjs.org/playwright/-/playwright-1.64.1.tgz",
+      "integrity": "sha512-HCrVhHr5QQuwYoswEUGTb7gGp522yflbv/ST8nF4sFWGuLjQCt17Q/EubpGGSNKYn1tsTCPZxqHhHCfVURu7UA==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "playwright-core": "1.64.1"
+      },
+      "bin": {
+        "playwright": "cli.js"
+      },
+      "engines": {
+        "node": ">=20"
+      }
+    },
+    "node_modules/playwright-core": {
+      "version": "1.64.1",
+      "resolved": "https://registry.npmjs.org/playwright-core/-/playwright-core-1.64.1.tgz",
+      "integrity": "sha512-BC4s8y6SEVA6Q1rSxZTto8hI1KUI3xXlHGZgvGqP4IqPdI/a6FX9H29IDNz7vKo9l21b6LfYosScPL6M3xxyDQ==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "playwright-core": "cli.js"
+      },
+      "engines": {
+        "node": ">=20"
+      }
+    },
     "node_modules/pngjs": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/pngjs/-/pngjs-5.0.0.tgz",