wallet.py requires NU5 activation

[zancas]

When I attempt to run the wallet test against a zallet that's not configured to expect NU5 activation I get this (unsurprising) error:

2026-03-20T00:04:08.725414Z  INFO zallet::commands::start: Wallet steady-state sync task exited wallet_sync_result=Err(Error(Context { kind: Sync, backtrace: Some(   0: <unknown>
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), source: Some(Indexer(InvalidData { message: "Missing Orchard tree state" })) }))

[linear]

COR-1110

[zancas]

This behavior is not observed when I build against the latest zallet.

[zancas]

I assumed that wallet.py passing when I changed which commit I built zallet 0.1.0-alpha.3 from was expected behavior.

If that's not the case, then I was naively optimistic closing this.

[oxarbitrage]

Fixed by #125 (merged in d4690c7). Regtest now defaults activation_heights to {"NU5": 1}, aligning zebra with zallet's NU5@height-1 regtest_nuparams, so the "Missing Orchard tree state" error is gone. Validated locally: create_cache builds the full 8-node cache and wallet.py runs against the aligned config.