e2e: add Mobile Safari + WebKit + Pixel projects to astro-kbve Playwright matrix

[h0lybyte]

Tracker: #11583

Problem

apps/kbve/astro-kbve/playwright.config.ts ships a single project — Desktop Chrome. UA-specific bugs (iOS Safari tap delay, WebKit client:only hydration race, mobile grid overflow) cannot be reached by this matrix. PR #11578 patched exactly this kind of bug — discovered in production, not in CI.

Acceptance

projects: [
  { name: 'chromium',     use: { ...devices['Desktop Chrome'] } },
  { name: 'webkit',       use: { ...devices['Desktop Safari'] } },
  { name: 'mobile-safari',use: { ...devices['iPhone 13'] } },
  { name: 'mobile-chrome',use: { ...devices['Pixel 5'] } },
],

• All four projects run in CI on the existing astro-kbve e2e target
• Existing towerdefense.spec.ts either passes on all four, OR is explicitly project-gated
• Failing project shows up as a distinct row in the CI run, not a single chromium failure

[h0lybyte]

Shipped via PR #11633 (merged to dev in commit e93a234).

Status

• All four projects declared in apps/kbve/astro-kbve/playwright.config.ts: chromium, webkit, mobile-chrome (Pixel 7), mobile-safari (iPhone 14). Pixel 5 / iPhone 13 from the original spec swapped to current devices — same UA matrix, modern viewports.
• Existing towerdefense.spec.ts runs against all four (canvas-only assertions, no touch input gating needed).
• Per-project rows appear in CI as distinct strategy matrix entries.

CI plumbing follow-up (not blocking close)

Spotted while auditing: .github/workflows/docker-test-app.yml was only installing chromium. webkit install added in PR #11652 so ci-e2e actually exercises the new projects.

Closing — config side is complete.