feat(send): improve Lightning send failure recovery

[pwltr]

Summary

• Move Lightning send failures onto the failure screen with localized user-facing messages.
• Add retry support that resets Lightning payment routing caches, waits for local routing data to reload, and returns the user to the correct send confirmation flow.
• Fix retry freshness checks so RGS refresh no longer requires the remote snapshot timestamp to change after the local graph cache is reset.
• Prevent overlapping retry flows from stale failure screens by tracking Lightning retry state outside the recreated view.
• Consolidate PaymentFailureReason user-message mapping into PaymentFailureReason+UserMessage.swift with generic and send-specific contexts.
• Keep send-specific route/retry failure copy for the retry screen while using generic payment failure copy elsewhere.
• Fix stale Lightning node lifecycle state where the view model could think the node was running after the service node was gone.

Closes #483

Simulator.Screen.Recording.-.iPhone.17.-.2026-08-04.at.19.07.07.mov

[greptile-apps]

Greptile Summary

The PR moves Lightning failures into a dedicated retry flow, resets routing caches before retrying, and adds localized failure messages.

• Adds contextual payment-failure messaging and translations.
• Restarts Lightning and waits for refreshed graph and scorer data before returning to confirmation.
• Tracks retry state outside the recreated failure view to prevent overlapping retries.

Confidence Score: 4/5

The PR is not yet safe to merge because a failed Lightning stop can leave the wallet permanently stuck in the stopping lifecycle state.

The recovery path calls start() after a cache-reset error, but when the underlying stop throws, the state remains .stopping and start() returns without restoring the node.

Files Needing Attention: Bitkit/Views/Wallets/Send/SendFailure.swift; Bitkit/ViewModels/WalletViewModel.swift

Important Files Changed

Filename	Overview
Bitkit/Views/Wallets/Send/SendFailure.swift	Implements cache-reset and node-restart recovery, but a stop failure can leave the lifecycle stuck in .stopping.
Bitkit/ViewModels/WalletViewModel.swift	Adds routing-cache reset and freshness polling while retaining a lifecycle state that the retry restart cannot recover.
Bitkit/Views/Wallets/Send/SendSheet.swift	Adds retry-route metadata and restores the corresponding confirmation flow.
Bitkit/Extensions/PaymentFailureReason+UserMessage.swift	Centralizes generic and send-specific localized payment-failure mappings.

_{Reviews (2): Last reviewed commit: "feat(send): improve Lightning send failu..." | Re-trigger Greptile}

[pwltr]

Failing e2e seems unrelated, ready for review.