test: add Pest browser testing with SQLite :memory: schema

Set up end-to-end browser testing using Pest Browser Plugin + Playwright.
New v4 test suite uses SQLite :memory: database with pre-generated schema dump
(database/schema/testing-schema.sql) instead of running migrations, enabling
faster test startup.

- Add pestphp/pest-plugin-browser dependency
- Create GenerateTestingSchema command to export PostgreSQL schema to SQLite
- Add .env.testing configuration for isolated test environment
- Implement v4 test directory structure (Feature, Browser, Unit tests)
- Update Pest skill documentation with browser testing patterns, API reference,
  debugging techniques, and common pitfalls
- Configure phpunit.xml and tests/Pest.php for v4 suite
- Update package.json and docker-compose.dev.yml for testing dependencies

package-lock.json

@@ -10,7 +10,8 @@
                 "@tailwindcss/typography": "0.5.16",
                 "@xterm/addon-fit": "0.10.0",
                 "@xterm/xterm": "5.5.0",
-                "ioredis": "5.6.1"
+                "ioredis": "5.6.1",
+                "playwright": "^1.58.2"
             },
             "devDependencies": {
                 "@tailwindcss/postcss": "4.1.18",
@@ -2338,6 +2339,50 @@
                 "url": "https://github.com/sponsors/jonschlinkert"
             }
         },
+        "node_modules/playwright": {
+            "version": "1.58.2",
+            "resolved": "https://registry.npmjs.org/playwright/-/playwright-1.58.2.tgz",
+            "integrity": "sha512-vA30H8Nvkq/cPBnNw4Q8TWz1EJyqgpuinBcHET0YVJVFldr8JDNiU9LaWAE1KqSkRYazuaBhTpB5ZzShOezQ6A==",
+            "license": "Apache-2.0",
+            "dependencies": {
+                "playwright-core": "1.58.2"
+            },
+            "bin": {
+                "playwright": "cli.js"
+            },
+            "engines": {
+                "node": ">=18"
+            },
+            "optionalDependencies": {
+                "fsevents": "2.3.2"
+            }
+        },
+        "node_modules/playwright-core": {
+            "version": "1.58.2",
+            "resolved": "https://registry.npmjs.org/playwright-core/-/playwright-core-1.58.2.tgz",
+            "integrity": "sha512-yZkEtftgwS8CsfYo7nm0KE8jsvm6i/PTgVtB8DL726wNf6H2IMsDuxCpJj59KDaxCtSnrWan2AeDqM7JBaultg==",
+            "license": "Apache-2.0",
+            "bin": {
+                "playwright-core": "cli.js"
+            },
+            "engines": {
+                "node": ">=18"
+            }
+        },
+        "node_modules/playwright/node_modules/fsevents": {
+            "version": "2.3.2",
+            "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
+            "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
+            "hasInstallScript": true,
+            "license": "MIT",
+            "optional": true,
+            "os": [
+                "darwin"
+            ],
+            "engines": {
+                "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
+            }
+        },
         "node_modules/postcss": {
             "version": "8.5.6",
             "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.6.tgz",