Discover funded task accounts for Solana indexing

[hexcreator]

Goal

Discover funded task accounts instead of scanning only known account addresses.

Context

The current live scanner can read a deterministic task account when given the matching signed intent. A usable indexer needs account discovery and batching.

Suggested Scope

• Explore Solana RPC options for program-owned account discovery.
• Define filters for the 276-byte task account layout/discriminator.
• Batch discovered accounts into tasc.funding.batch.solana.
• Preserve existing signed-intent admission checks.

Acceptance Criteria

• Read-only plan mode describes RPC calls and filters.
• Fixture mode proves multiple discovered accounts can be admitted/rejected.
• Scanner does not publish tasks without matching signed intents.

Non-Goals

• Do not require a hosted database.
• Do not weaken admission checks to make discovery easier.