fix(logpoller): abort loop on loader error

[jadepark-dev]

• Return error on loader failures to trigger retry on next poll cycle, preventing data loss from incomplete transaction data
• Parse errors are treated as non-critical in the logpoller lifecycle management. block checkpoint still advances with a warning, if we have parsing error with known-indexable contracts, this should trigger an alert since it indicates a malformed onchain cell data OR corrupted data from chain itself