scaffold(mobile): branch setup — audit harness, spec, plan, gitignore + client-portal cleanup

Pre-execution baseline for the mobile foundation PR:

- Mobile audit harness (tests/e2e/audit/mobile.spec.ts + mobile-audit Playwright project) — visits every page at four anchor iPhone viewports (375/393/402/440), screenshots full-page to .audit/mobile/, generates index.md
- Design spec (docs/superpowers/specs/2026-04-29-mobile-optimization-design.md) — adaptive shell + responsive content; full active-iPhone-range coverage; foundation + per-page migration phases
- Implementation plan (docs/superpowers/plans/2026-04-29-mobile-foundation.md) — 24 TDD tasks for the foundation PR
- .gitignore: ignore /client-portal/ (legacy nested Nuxt repo) and /.audit/ (regenerable screenshots)
- Remove phantom client-portal gitlink (mode 160000 with no .gitmodules)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

playwright.config.ts

@@ -75,6 +75,22 @@ export default defineConfig({
         viewport: { width: 1440, height: 900 },
       },
     },
+    {
+      // Mobile / tablet audit — visits every page in headed Chromium at iPhone
+      // viewports (portrait), screenshots full-page to .audit/mobile/<viewport>/,
+      // and writes an index.md. Depends on `setup` for seeded admin + port-role.
+      name: 'mobile-audit',
+      testMatch: /audit\/mobile\.spec\.ts/,
+      dependencies: ['setup'],
+      timeout: 600_000,
+      use: {
+        headless: false,
+        launchOptions: { slowMo: 200 },
+        screenshot: 'off',
+        video: 'off',
+        trace: 'off',
+      },
+    },
   ],
 
   // Don't start the dev server — we expect it to already be running