test: add probeNode devtools command

[piotr-iohk]

Closes #1000

This PR adds a probeNode devtools command for mainnet keysend probe targets used by nightly Lightning monitoring.

Description

• Adds ProbeNode to the debug devtools ContentProvider, mirroring the existing invoice probe flow
• Accepts nodeId, amountSats/amountMsat, targetName, and timeoutSeconds over adb
• Delegates to LightningRepo.sendProbeForNode() and returns the same success/failure JSON shape as probeInvoice

Pairs with:

• feat: add nodeId probe target support bitkit-e2e-tests#177
• synonymdev/bitkit-nightly#22

Preview

QA Notes

Manual Tests

• 1. Build mainnet debug E2E APK → install on emulator/device with probe wallet.
• 2. With node running, adb shell content call to probeNode with a known pubkey and 1000 sats → JSON success response.
• 3. regression: adb shell content call to probeInvoice with a test BOLT11 → still returns expected success/failure JSON.

Automated Checks

• just compile passed locally.
• Existing LightningRepoTest.sendProbeForNode covers repo delegation; no new unit tests for devtools (same precedent as probeInvoice).
• CI: standard compile, unit test, and detekt checks run by the PR bot.

Made with Cursor

[jvsena42]

utAck

[ovitrif]

LGTM
utAck