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/e2e/layout.spec.ts

@@ -208,7 +208,7 @@ test.describe('harness self-validation — injected defects', () => {
 
     // REMOVE the injected style by navigating (page.reload drops inline style tags)
     // then re-measure — must be ≥ 44px again
-    await styleHandle.evaluate((el) => el.remove())
+    await styleHandle.evaluate((el) => (el as Element).remove())
     const boxAfterRemoval = await calTab.boundingBox()
     expect(
       boxAfterRemoval,
@@ -248,7 +248,7 @@ test.describe('harness self-validation — injected defects', () => {
     ).toBeGreaterThan(overflowWithDefect.clientWidth)
 
     // REMOVE the injected style — overflow must clear
-    await styleHandle.evaluate((el) => el.remove())
+    await styleHandle.evaluate((el) => (el as Element).remove())
     const overflowAfterRemoval = await page.evaluate(() => ({
       scrollWidth: document.documentElement.scrollWidth,
       clientWidth: document.documentElement.clientWidth,