fix: protect nostrconnect handshake from app backgrounding + paste/UX polish (build 62)

[DocNR]

Summary

• Wraps the nostrconnect handshake Task in UIApplication.beginBackgroundTask so it survives the user swiping Clave away to launch the client app mid-flight. Previously the unguarded Task would get suspended by iOS within ~5–10s of backgrounding, freezing the URLSessionWebSocketTask mid-await; the critical 2–3s window of connect → publish ack → pair-client never completed, so the proxy never registered URI relays for secondary subscription and the client's follow-up RPCs vanished into ephemeral kind:24133 events nobody was listening on. The 30s background budget is comfortable margin over the ~15–20s handshake.
• Adds a "Paste Nostrconnect URI" button above the paste field — one tap instead of tap-field/long-press/paste.
• Softens the connecting overlay copy to "Connecting... / Stay in Clave for a few seconds" rather than relying on the bg-task alone.
• Fixes the "Connect as @..." approval button wrapping awkwardly for long emoji-decorated display names: lineLimit(1) + truncationMode(.tail) + minimumScaleFactor(0.7).

Bunker flow is unaffected (NSE-owned via APNs, has its own ~30s wake budget). Build 60 → 62 (61 was burned in an earlier archive that didn't ship).

Plan: ~/.claude/plans/run-bootstrap-i-m-gentle-fairy.md

Test plan

Local Debug confirmed the nostrconnect handshake works (Wisp client reported a fragile-connection issue resolved by the bg-task fix), but Debug uses sandbox APNs so the full sign-flow needs TestFlight:

• TestFlight install of build 62
• Golden path: paste fresh nostrconnect:// URI → Approve → swipe Clave to app switcher and launch the client → client receives connect-ack and get_public_key round-trips
• Stay-in-Clave control: repeat without swiping; no regression vs build 60
• Paste button: clipboard contains valid URI → tap "Paste Nostrconnect URI" → ApprovalSheet presents directly
• Paste button — empty clipboard: tap → "Clipboard is empty." inline error
• Paste button — invalid URI: tap → "That doesn't look like a valid nostrconnect URI." inline error
• Connect-as button: approve sheet for an account with a long emoji-decorated display name renders the button single-line with tail truncation, no wrap
• Force-quit case (documented limitation): swipe Clave away from app switcher within 15s of Approve → handshake fails (UIBackgroundTask doesn't cover process termination); user sees error in Clave on next open
• Bunker URI sanity: unchanged code path; existing bunker pairings + sign requests still work via NSE
• Existing connections: build 60 era pairings still receive sign requests via the proxy/APNs/NSE pipeline

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