feat: add send payment pending UI

[ovitrif]

This PR adds a pending payment UI for Lightning sends that take longer than expected (e.g. hold invoices).

Description

1. Adds a SendPendingScreen with an hourglass animation, shown when a Lightning payment exceeds the 10-second timeout without resolving
2. Adds PendingPaymentResolution tracking in LightningRepo so payment success/failure events are routed back to the pending screen
3. Handles both resolution paths: navigates to success sheet on completion, or error sheet on failure
4. Handles invoices in background if sheet was dismissed with toast for success or error
5. Adds a "View Details" button that links to the activity detail once the payment activity is synced
6. Toasts for the pending payment handled by the sheet only fire when the user has closed the sheet, if pending sheet is visible, rely on sheets UI.
7. Adds mechanism to ensure older pending payments still show toast on settled/canceled, even if UI shows sheet for new pending payment.

Preview

Recording

• Note: Video speed is at 1.75x playback speed.
• Script
  1. Pending UI > Details > List > Settle > Error Toast
  2. Pending UI > Cancel > Error Sheet
  3. Pending UI > Settle > Success Sheet
  4. Pending UI > Details > List > Cancel Toast

Recording	Edge Cases
tests_1.75x.mp4	edges_1.75x.mp4

QA Notes

Setup

1. Startup bitkit-docker: docker compose up -d
2. Start emulator via Android Studio
3. Run this first:

   adb reverse tcp:9735 tcp:9735 && \
   adb reverse tcp:3000 tcp:3000 && \
   adb reverse tcp:60001 tcp:60001 && adb reverse --list

4. Apply local-electrum.patch to connect to local Electrum, then build and run on emulator:

   curl -sL https://gist.githubusercontent.com/ovitrif/ac13a7ba09efd4c12bee0a1b4cc27f4a/raw/local-electrum.patch | git apply

5. Open a channel, skip first 4 steps

Use ./bitcoin-cli in bitkit-docker for hold invoices ops:

./bitcoin-cli holdinvoice 42 -m 'test' # create
./bitcoin-cli settleinvoice __preimage__ # settle
./bitcoin-cli cancelinvoice __hash__ # cancel

Tests

• Pending screen should show on hold invoices
• Payment resolves to success sheet when on sheet
• Payment resolves to error sheet when on sheet
• View Details button opens pending activity detail
• Close button + settle/cancel -> resolves to toast
• UI should match FIGMA / iOS
• QuickPay for cancelled/settled pending payment

Edge Cases

No need for reviewer(s) to test edge cases, they're listed here for transparency into what was dev-tested.

• Back nav from success/error sheet should dismiss it
• Pending screen visible + settle → no toast, success screen shown
• Pending screen visible + cancel → no toast, error screen shown
• Sheet closed + settle → toast shown
• Sheet closed + cancel → toast shown
• Multi pending payment resolution
  • Pay hold invoice1 (old) + dismiss sheet
  • Pay hold invoice2 (new) + settle/cancel old invoice while on pending sheet → toast shown
  • Settle/cancel new invoice → no toast, success/error screen shown
• Scanner (QuickPay on/off), paste, cancel invoice, tap 'Try Again' → Send Recipient shown
• Paste 0-amount hold invoice via send + cancel + try again → Send Recipient

🤖 Generated with Claude Code

[pwltr]

• description text "This payment..." has wrong colour
  • should use: White64

• success/failed toasts have wrong text
  • should use same as feat(send): add pending payment UI bitkit-ios#465

• bug when tapping button "Try Again" (probably unrelated to this PR)
  • instead of navigating to send recipient, app navigated to send success screen.

Screen.Recording.2026-03-06.at.15.37.58.mov

[piotr-iohk]

Note / observation. There is a little discrepancy in behavior between Android and iOS:

In those cases iOS shows both toast and success / error screen:

• Pending screen visible + settle → no toast, success screen shown
• Pending screen visible + cancel → no toast, error screen shown

This edge case is not handled in iOS

Multi pending payment resolution

• Pay hold invoice1 (old) + dismiss sheet
• Pay hold invoice2 (new) + settle/cancel old invoice while on pending sheet → toast shown [on iOS toast + success screen for old tx is shown and pending screen is dismissed]
• Settle/cancel new invoice → no toast, success/error screen shown

Probably should be reported in iOS.

[ovitrif]

@pwltr fixes:

Error	Try Again
	fixTryAgain.mp4

🆕 Dev tests

New dev tests, also added to PR description.

• Scanner (QuickPay on/off), paste, cancel invoice, tap 'Try Again' → Send Recipient shown
• QuickPay for cancelled/settled pending payment
• Paste 0-amount hold invoice via send + cancel + try again → Send Recipient

[pwltr]

utACK

[ovitrif]

I fixed the toast message in this PR but the error sheet message is also misleading, I will remove in next PR, then on this error screen we'll have parity with iOS:

Android	iOS

[pwltr]

I fixed the toast message in this PR but the error sheet message is also misleading, I will remove in next PR, then on this error screen we'll have parity with iOS:

That screen needs work on both platforms. Design has some improvements to status quo but needs to be adjusted somewhat. For LN payments "Transaction" is not accurate, should be "Payment". And we should try to show a user actionable error description as well as we can.