fix: default prover-db indexer to disabled unless explicitly enabled

[JayWhite2357]

Rationale for this change

The offchain worker logged an error every block whenever the prover-db indexer URL wasn't configured. Running offchain workers without opting into the indexer is a normal configuration, not an error state.

What changes are included in this PR?

Add a prover_db_indexer/enabled config key (default false) that gates the OCW consumer.

Are these changes tested?

Yes

[github-actions]

1.70.0

Bug Fixes

• default prover-db indexer to disabled unless explicitly enabled (360803d
• fallback to client hash when is missing (95794da
• make on chain indexer keys saturate rather than default to (5f794de
• use finalized block in prover-db-indexer (50438ab

Features

• add helper that queries the client for s. (4fc3952
• add client native interface and extenality (d9c6c4d
• add generic config key-value store for offchain workers (117b845
• adds (a5b581d
• Document Snapshot Download Process (4c2608b
• drop from prover_db_indexer (b3381c5
• register client externality to offchain worker (338c213
• use client for (6679c06
• use generic key value config for prover_db_indexing instead of storage/CLI based config (faff564

[JayWhite2357]

AI attribution: largely AI generated, with small manual refinements.