test: Added sandboxed, isolated Chromium first-run coverage with stat...

- package.json
- package-lock.json
- .gitignore
- playwright.config.ts
- e2e/fixtures.ts
- e2e/smoke.spec.ts
- tests/svg-image.test.tsx

GSD context:
- Milestone: M001 - Merge upstream v0.4.0 into the Gitea fork
- Slice: S02 - Verify combined application behavior
- Task: T01 - Added sandboxed, isolated Chromium first-run coverage with stateful synthetic API fixtures and fail-closed network boundaries.

GSD-Task: S02/T01

package.json

@@ -56,8 +56,8 @@
 		"mdast-util-from-markdown": "2.0.3",
 		"mdast-util-math": "3.0.0",
 		"media-chrome": "^4.19.2",
-		"micromark-extension-math": "3.1.0",
 		"mermaid": "^11.17.0",
+		"micromark-extension-math": "3.1.0",
 		"motion": "^13.1.1",
 		"nanoid": "^6.0.1",
 		"next": "^16.4.3",
@@ -82,6 +82,7 @@
 	},
 	"devDependencies": {
 		"@next/eslint-plugin-next": "^16.4.3",
+		"@playwright/test": "^1.64.1",
 		"@tailwindcss/postcss": "^4.3.3",
 		"@types/node": "^24.0.0",
 		"@types/react": "^19.2.18",