Update zodl for rebased SDK

[greg0x]

Summary

• wire the rebased Android SDK backend into the local included build
• adapt voting crypto code to call the SDK backend/JNI voting APIs directly
• update voting call sites for the rebased SDK witness, commitment, and cast-vote signing APIs

Validation

• ./gradlew :ui-lib:compileZcashtestnetInternalDebugKotlin
• ./gradlew :ui-lib:compileZcashtestnetInternalDebugUnitTestKotlin
• ./gradlew :ui-lib:testZcashtestnetInternalDebugUnitTest
• ./gradlew :app:assembleZcashtestnetInternalDebug

Notes

• detektAll and ktlint currently fail on origin/shielded-vote before this branch, so they are not included as branch-specific validation.

[greg0x]

Handoff context: zodl companion for the updated shielded-vote SDK known state.

Goal

• Make zodl build and run against the rebased SDK shielded-vote state from SDK #1924.
• The SDK goal was to preserve the known shielded-vote fixes while moving onto upstream main, which already contains PR6/PR7 split work (SDK #1951 and SDK #1952) plus SDK #1937.
• This zodl PR is a compatibility/testing branch for that SDK state, not a separate feature rewrite.

Current state

• This PR is greg/update-zodl-android-for-rebased-sdk -> shielded-vote; current head is 7f2d3593.
• The repo is set up to consume the local SDK checkout through SDK_INCLUDED_BUILD_PATH=../zcash-android-wallet-sdk.

What changed to get the app compiling/running

• Added cash.z.ecc.android:zcash-android-backend to zodl dependencies and included-build substitution, so the app can use the local SDK :backend-lib alongside :sdk-lib.
• Removed the zodl DI binding to the old SDK TypesafeVotingBackend; that wrapper is now internal to the rebased SDK path.
• Reworked VotingCryptoClientImpl to manage VotingRustBackend / VotingRustBackend.VotingDb directly and map JNI voting models back into zodl app models.
• Added SynchronizerProvider.getVotingWalletDbPath() as a narrow shim around the SDK voting DB path, because zodl still needs that path for voting setup and recovery flows.
• Updated witness generation/storage for the rebased SDK API: pass networkId into witness generation, select the bundle-specific notes from the witness result, and pass those bundle notes into storeWitnesses.
• Updated vote commitment/signing call sites: pass accountIndex into commitment generation, and pass the full commitment JSON into cast-vote signing instead of reconstructing the signature input from individual fields.
• Updated the affected test fake for the new SynchronizerProvider API.

Decisions made

• Use the rebased SDK API as-is rather than re-exposing the old SDK wrapper just for zodl.
• Keep the wallet DB path shim intentionally narrow; it is only there to let the app exercise the current SDK voting path.
• Keep this PR focused on SDK compatibility and testing. Avoid unrelated zodl cleanup or repo-wide formatting churn.
• Do not treat detektAll / ktlint as branch-specific blockers here because those global tasks already fail on origin/shielded-vote before this branch.

PR8 boundary

• This PR follows the SDK #1924 API surface, including the recovery/full-commitment JSON pieces that overlap with PR8 (SDK #1953).
• It does not port PR8 wholesale into zodl.
• Anything that is PR8-only and not required by the rebased SDK #1924 API should stay on the PR8 review/test track.

Validation already run

• ./gradlew :ui-lib:compileZcashtestnetInternalDebugKotlin
• ./gradlew :ui-lib:compileZcashtestnetInternalDebugUnitTestKotlin
• ./gradlew :ui-lib:testZcashtestnetInternalDebugUnitTest
• ./gradlew :app:assembleZcashtestnetInternalDebug

Suggested next verification

• Check out SDK PR SDK #1924 and this zodl PR together in the workspace.
• Re-run the validation commands above after pulling both branches.
• Install the :app:assembleZcashtestnetInternalDebug APK on an emulator/device and exercise the voting flow against the rebased SDK, especially witness generation/storage, vote commitment generation, cast-vote signing, hotkey seed propagation, and recovery/share tracking.