[P1] Audit: PWA install flow needs stronger in-product prompt and browser-specific clarity

[baixiangcpp]

Imported from the byteflow.tools deep audit on 2026-06-22.

Problem: byteflow.tools supports PWA installation and has an install guide, but the product can do more to explain when installation is available, why it helps, and how the flow differs across Chrome, Edge, Safari, Firefox, Android, and iOS.

Affected URL:

• https://byteflow.tools/en/install-app

Reproduction steps:

1. Open /en/install-app in desktop Chrome.
2. Check whether the browser install prompt is surfaced or only explained.
3. Review instructions for Chrome, Android, iOS Safari, Edge, and Firefox.
4. Test installability after loading a few tools.
5. Check how offline support is explained.

Expected behavior: users should see an in-product install CTA when install is available and clear fallback instructions when it is not.

Actual behavior: install documentation exists, but the live prompt and browser-specific clarity can be stronger.

Impact: fewer users install the PWA, reducing repeat usage and offline adoption.

Proposed fix:

• Use beforeinstallprompt where supported.
• Add a visible install CTA in header or tool pages for eligible users.
• Show browser-specific instructions conditionally.
• Add screenshots or short animated guides.
• Explain offline boundaries for browser-local vs external-request tools.
• Track safe aggregate install CTA impressions and completions.

Acceptance criteria:

• Install CTA appears only when relevant.
• Install guide detects browser family and highlights correct steps.
• Offline limitations are clear.
• Users can dismiss the prompt.
• PWA install and offline smoke tests pass.

[baixiangcpp]

Closed as completed by the canonical BF audit backlog work. This older non-BF audit issue duplicates work now merged through PRs #209-#219, with the BF issues closed and guard/test coverage in place. The remaining non-duplicate follow-up is #7, which stays open because the upstream Next/PostCSS advisory is not fixed yet.