lokahi-interop: verification round loop

The lockstep round: observe (pull-based atomic snapshot queries against ChainControllers + read-only EL clients for receipts/payloads/outputs) → pure decide (Wait | Advance | Invalidate | Rewind) → WAL → apply. Cold-start init + 7-day log backfill, L1-consistency checks, halted state for permanent errors (e.g. unrecoverable SafeDB history gaps). Happy path only (Advance/Wait); Invalidate/Rewind apply in phase 4. Keep observe/decide pure — unit tests ported from op-supernode + parity vectors.

Depends on: #22534, #22535, #22532 (N-chain service), #22527 (query handler).

🤖 *Co-created with Claude (Fable 5)*

Start by reviewing dependencies #22534, #22535, #22532, and #22527, then compare the observe/decide behavior with op-supernode and the parity vectors. Trace the ChainControllers and read-only EL client inputs through the lockstep round. Done means cold-start initialization, seven-day backfill, L1 consistency checks, WAL and apply flow, plus halted handling for permanent errors, with the happy path covering Wait and Advance.

Written by the indexing model from the issue text.