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

tests/svg-image.test.tsx

@@ -179,7 +179,9 @@ it("the fullscreen button opens the same SVG image and inversion; download keeps
 		// Intercept only the download anchor; never navigate or write a real file.
 		dom.document.createElement = ((...args: Parameters<typeof originalCreateElement>) => {
 			const element = originalCreateElement.apply(dom.document, args);
-			if (args[0] === "a") {
+			// Playwright imports Electron's final createElement('webview') overload;
+			// Parameters<> sees that overload, not the runtime string tag.
+			if ((args[0] as string) === "a") {
 				element.click = () => { clicked = { name: element.getAttribute("download")!, href: element.getAttribute("href")! }; };
 			}
 			return element;