When a card's auto-open is gated on `confirmThenOpen`, the URL also
appears inside the surrounding `note(...)` as a copy-paste fallback —
rendered dim because on a GUI device the auto-open is doing the
heavy lifting and the printed URL is just an incidental backup.
On headless devices the auto-open doesn't run (per #2145), so the
URL inside the note is the user's *only* path forward. A dim URL
reads as "incidental reference" exactly when it should be reading
as "this is the action."
Adds `formatNoteLink(url)` to setup/lib/browser.ts:
- GUI device → `k.dim(url)` (unchanged from today)
- Headless device → `Get started: <url>` at full strength
Replaces five call sites (Discord ×3, Slack ×1, Telegram ×1).
Single helper, atomic switch via the same `isHeadless()` plumbing
introduced in #2145, so the headless behavior across all five
flows stays in sync.
6863e0f63b