fix: nostrconnect connect-flow polish (same-device overlay copy + QR rescan dedup)

[DocNR]

Two related connect-flow polish bugs surfaced during build 66 verification, both contained to ConnectNostrconnectTabView.swift (+ overlay copy in ConnectSheet.swift).

1. Misleading "Stay in Clave" overlay for same-device nostrconnect

The overlay shipped in build 62 (PR #26) is actively misleading for same-device nostrconnect pairs — iOS suspends the client app's WebSocket subscription as soon as it loses foreground, so users who follow that advice never receive the connect-response Clave publishes. Quick-switching back to the client app is what actually completes the handshake. Verified on build 66 against noStrudel and Jumble.

Switch the overlay subtitle based on URI provenance:

• paste/text-field → same-device → "Switch back to your client app to finish connecting. Clave keeps running in the background."
• QR scan → cross-device (camera scanned another screen) → keep "Stay in Clave for a few seconds".

2. QR scanner re-fires the same code after ApprovalSheet cancel

When the user scans a nostrconnect QR, ApprovalSheet presents and the scanner stops. Cancelling ApprovalSheet flips parsedURI back to nil and the existing onChange handler re-arms the scanner so a different QR can be scanned without closing+reopening the sheet. But the QR the user just scanned is almost always still in frame — within ~1s the AVFoundation pipeline detects it again, looping the user straight back into ApprovalSheet they just dismissed.

Dedup at handleScannedCode against a per-mount lastAcceptedScanCode. Each nostrconnect URI carries a fresh secret, so different sources produce different codes and legitimate retries pass through. State clears when this view re-mounts (i.e. ConnectSheet is reopened).

Why provenance is plumbed at the parse callback, not in AppState

The "Connecting…" overlay is only rendered in ConnectSheet.connectingOverlay — i.e. the in-app paste/QR-scan flow. The deeplink path in HomeView (pendingNostrconnectURI → deeplinkApprovalURI) runs appState.handleNostrConnect in a fire-and-forget Task with no progress UI, so it doesn't need a same-device flag. The provenance distinction is added as a top-level NostrConnectURISource enum in ConnectNostrconnectTabView.swift and threaded through the onParsed callback into ConnectSheet's lastParsedSource state — no AppState changes, no protocol changes.

Bundles docs/nip46-compatibility.md updates

The doc edit was already in the working tree from earlier today's verification work and explains the exact iOS WebSocket suspension constraint this code change addresses (same 2026-05-07 date stamp, same build-66 verification). Shipping them together keeps the public-facing explanation and the in-app UX consistent in one atomic change.

• Added "iOS same-device pairing" section recommending bunker:// for same-device iOS pairing; explains why nostrconnect:// is brittle there with nostr-toolslimit: 0 + frozen-WebSocket details; lists mitigations for clients that want to support it.
• Added "Improving post-pair delivery reliability for Clave-paired clients" note recommending wss://relay.powr.build/ in nostrconnect URI relay sets so client→Clave RPCs catch on the proxy's primary subscription regardless of foreground state.

Out of scope

• Auto-dismissing the overlay early when the handshake reports success — would require surfacing a "first response received" callback from handleNostrConnect, and the overlay is rarely seen past ~3s anyway because the user has already switched to the client app. Skip.
• Adding a progress overlay to the deeplink path in HomeView. Different code path, separate UX call. Skip.
• Reframing the Connect tab UX to steer same-device users away from nostrconnect entirely (e.g. "Recommended for same-device" hint on Bunker, or a topology-first picker). Worth doing — separate sprint, will brainstorm next.
• Stage 3b/3c god-object refactor — explicitly decoupled.

Test plan

Same-device overlay copy

• Install build with this change on iPhone.
• Open noStrudel (same-device, iOS Safari/standalone), generate a nostrconnect:// URI, copy it.
• Open Clave → Connect a Client → Nostrconnect tab → tap "Paste Nostrconnect URI" → approve.
• Confirm overlay subtitle reads "Switch back to your client app to finish connecting. Clave keeps running in the background."
• Quick-switch to noStrudel, confirm pairing completes.
• Repeat with Jumble.
• (Optional) Repeat with QR-scan path against a cross-device client (e.g. desktop nostrudel showing a QR), confirm overlay still says "Stay in Clave for a few seconds".

QR rescan dedup

• On a different device, generate a nostrconnect QR (any web client). Point Clave's nostrconnect tab camera at it.
• Confirm ApprovalSheet appears.
• Tap Cancel on ApprovalSheet — keep the QR in frame.
• Confirm camera viewfinder is live (not frozen) but ApprovalSheet does NOT re-present for the same QR.
• Generate a new QR (refresh client) — confirm new QR scans normally.

Build / unit tests

• xcodebuild test -scheme Clave — all suites pass on iPhone 17 sim (run on first commit; QR fix is a strict superset and has no test impact).

🤖 Generated with Claude Code