feat(report): rebrand HTML test report as Mobilewright

[krismuhi]

Summary

• Replaces all Playwright branding (title, favicon, header) with Mobilewright in HTML test reports
• Adds a clickable Mobilewright logo in the report header that links to the GitHub repo
• Screenshot thumbnails now render at max 250px width with click-to-fullscreen overlay (Escape or click to dismiss)

Changes

• packages/mobilewright/src/reporter.ts — new brandReport() function that post-processes Playwright's HTML report output
• packages/mobilewright/src/cli.ts — calls brandReport() after test run when --reporter html is used
• packages/mobilewright/assets/mobilewright-icon.png — icon used as favicon and header logo
• packages/mobilewright/package.json — includes assets/ in published files

Test plan

• Run mobilewright test --reporter html and open the generated report
• Verify browser tab shows "Mobilewright Test Report" with the mobilewright favicon
• Verify header shows mobilewright logo + name, clicking it opens the GitHub repo
• Verify screenshots render as 250px thumbnails
• Click a screenshot and verify fullscreen overlay appears
• Press Escape or click overlay to dismiss

[krismuhi]

im not happy about this change.