feat: convert scanner to bottom sheet

[jvsena42]

FIGMA

This PR converts the QR scanner from a full-screen navigation route into a proper bottom sheet, consistent with other sheets in the app (Send, Receive, Backup, etc).

Description

1. Removes NavController dependency from QrScanningScreen and simplifies it to accept onBack/onScanSuccess callbacks
2. Creates QrScanningSheet that wraps the scanner in a SheetHost-compatible composable with sheetHeight()
3. Adds Sheet.QrScanner type and result routing via AppViewModel.showScannerSheet(onResult)
4. Updates all call sites (TabBar, FundingAdvanced, SendSheet, ExternalConnection, ProbingTool, ElectrumConfig, RgsServer) to use the sheet pattern
5. Removes Routes.QrScanner navigation route and navigateToScanner() extension
6. Removes the inSheet conditional styling from scanner and camera permission views, always using sheet styling

Preview

normal-payment.mp4

send-sheet.mp4

probing.mp4

quickpay.mp4

QA Notes

1. Tab bar scanner

   • Tap the scan icon in the bottom tab bar
   • Verify the scanner opens as a bottom sheet (drag handle visible, slides up)
   • Scan a valid QR code and verify it routes correctly (e.g., opens send flow for a Bitcoin address)

2. Send sheet scanner

   • Open Send sheet, navigate to the QR scanner route within it
   • Scan a QR code and verify it pops back and processes the result

3. Settings screens (for-result pattern)

   • Navigate to Electrum Config, tap the scan icon
   • Scan a QR code with server details and verify the scanned value populates the input field

• Repeat for RGS Server

• For External node

• And Probing Tool screens

4. Camera permission denied

   • Deny camera permission and verify the denied content displays correctly with sheet styling

5. Gallery and paste

   • Test picking a QR code image from gallery
   • Test pasting from clipboard

[jvsena42]

Drafted to implement the new "camera disabled" design

[jvsena42]

Drafted to implement the new "camera disabled" design

Drafted to implement the new "camera disabled" design

I'll do it in other branch to don't make the PR too big

[jvsena42]

drafted to investigate e2e failure

[jvsena42]

@piotr-iohk I see "127.0.0.1:6001:s" on the input of this test. Is it expected?
https://github.com/synonymdev/bitkit-android/actions/runs/23014213473/job/66942585911?pr=840