refactor: lazy sync requests and batched payment store updates

[ben-kaufman]

This PR:

1. Splits wallet_sync_request into separate full-scan and incremental methods so only the needed request type is built per sync cycle
2. Introduces a WalletSyncRequest enum to carry the chosen sync variant through the pipeline
3. Spawns primary and additional wallet syncs concurrently in a single JoinSet instead of running primary sequentially first
4. Batches update_payment_store_for_all_transactions and write_node_metrics into a single call after all wallet updates are applied
5. Fixes a pre-existing bug where additional wallet sync timestamps were set even when apply_update_for_address_type failed

QA Notes

Testing

• cargo test passes
• cargo clippy clean
• Verify Electrum sync path works with multiple address types
• Verify Esplora sync path works with multiple address types
• Confirm payment store is updated correctly after sync

Notes

• No API changes — internal refactor only, no binding regeneration needed
• The apply_update and apply_update_for_address_type methods now require callers to call update_payment_store_for_all_transactions afterward (documented via doc comments)

Made with Cursor

[ovitrif]

@ben-kaufman Each change updating the bindings must bump version number, otherwise it's (close to) impossible to consume the new version of the dependency in the apps.

Can you please make this change and regenerate bindings?

Thanks in advance 🙏🏻

[ovitrif]

No API changes — internal refactor only, no binding regeneration needed

This is not true. Bindings are NOT only the communication interface, but also the end-result of what exactly those methods end up calling, as native code..

So, with each update to the iOS XCFramework or the Android .so files, there should be a new version, otherwise the apps won't be able to leverage this "logic" change without changes to the bindings interface.

Claude, you'd better learn this good. (seems both the Claude reviews and the bot tagging with @claude is still broken. Likely token issue, because I ran /install-github-app while I wasn't admin of the repo. Will have to redo the routine in a new PR.