enhancement: optimized reorg handling by deferring checks to end of stream (historic)

[yug49]

Resolves #227

Description

This PR optimizes the historic/sync scanning modes by deferring reorg checks until after all block ranges have been streamed.

Changes

1. stream_historical_range in common.rs:

• Phase 1: Stream all finalized blocks without any reorg checks (unchanged)
• Phase 2: Stream all non-finalized block ranges without intermediate reorg checks
• After streaming the last range, check if the end block still exists (single reorg check)
• If a reorg is detected (BlockNotFound), send ReorgDetected notification and re-stream all non-finalized blocks
• Repeat until stable (end block exists or has become finalized)

2. handle_historical in block_range_scanner.rs:

• Removed ReorgHandler instantiation and parameter passing (no longer needed for historic mode)

3. sync_handler.rs:

• catchup_historical_blocks no longer requires reorg_handler parameter
• Reorg handling during sync's historical phase now uses the optimized approach