Firefox / Chrome-style small pill at the bottom-left of the window
showing the href when the pointer hovers a link, hidden when the
pointer leaves. Fed by webContents.update-target-url on every tab;
auto-sizes to its text via an IPC resize channel.
Cleared on tab switch so a lingering hover pill from tab A doesn't
carry across to tab B. Positioned by layout() so it tracks window
resizes.
New files link-status.html + link-status-preload.js registered in
build.files (GOTCHAS.md rule: missing entries silently omit from
the packaged app).
Not shipped yet — bundles into the next Theseus release.
