Reuse the open PWA window when an email link launches the app

[ralyodio]

The problem

Clicking a link in an alert email opened the installed PWA in a new window every time. Working through a digest left one app window per post.

Why

Alert emails link at our own reader page — packages/notify/src/render.js builds ${origin}/{slug}/read?p={guid} — so every click is an in-scope launch of rssamplifier.com. apps/web/public/manifest.webmanifest declared no launch_handler, which leaves the browser on auto, and auto opens a new app window per launch.

The fix

"launch_handler": {
  "client_mode": ["navigate-existing", "auto"]
}

navigate-existing focuses the most recently used app window and navigates it to the launched URL. That is the right mode here rather than focus-existing: the email link names a specific post, so landing on that post in the window already open is the point.

auto follows as the fallback for a browser that does not understand the first value, and for the case where no window is open yet.

What did not need changing

The notificationclick handler in sw.js already reuses a window by hand (clients.matchAll → focus → navigate). That path never went through the launch handler, which is why push taps were already fine and only email links were not.

sw.js VERSION goes v6 → v7 because /manifest.webmanifest is one of SHELL_URLS, so the copy taken at install is now stale. That bump is hygiene, not the fix — nothing serves the cached manifest today (.webmanifest falls through the fetch handler to the network), and the browser reads launch_handler over the network regardless.

Compatibility

Chromium 110+ honours it. Safari and Firefox ignore launch_handler and keep their current behaviour, so nothing regresses there. iOS home-screen installs open email links in Safari rather than the app either way.

Testing

• manifest.webmanifest parses as valid JSON with the new key
• node --check apps/web/public/sw.js passes
• No test asserts on either file (apps/web/test/proxy.test.js only checks that the proxy matcher skips these paths, unaffected)

🤖 Generated with Claude Code

https://claude.ai/code/session_013FR5zDT4DGJAmwDb6oVZ6n