fix(07-03): make e2e typecheck pass — add DOM lib to tsconfig.e2e, cast styleHandle el to Element

Playwright transpiles specs without typechecking (esbuild), so layout.spec.ts ran
green while `tsc -p tsconfig.e2e.json` failed: page.evaluate(() => document...)
callbacks need the DOM lib, and styleHandle.evaluate((el) => el.remove()) typed el as
Node (no .remove()). Phase 8 CI runs the typecheck gate, so this would have broken CI.
Adds DOM/DOM.Iterable to the e2e tsconfig (also covers 07-04 specs) and casts el to Element.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/pwa/tsconfig.e2e.json

@@ -2,7 +2,7 @@
   "extends": "./tsconfig.json",
   "compilerOptions": {
     "types": ["node"],
-    "lib": ["ES2023"]
+    "lib": ["ES2023", "DOM", "DOM.Iterable"]
   },
   "include": ["playwright.config.ts", "e2e/**/*"],
   "exclude": ["node_modules"]