chore(snapshot): remove unused/unsupported config knobs

[jolestar]

Overview

Several snapshot config knobs are unused/unsupported and add confusion.

Scope

Remove or hide the following if not implemented:

• workers
• max_traversal_time_hours
• enable_progress_tracking
• deduplication_strategy (non-RocksDB)
• enable_bloom_filter
• deduplication_batch_size

Acceptance Criteria

• Unused knobs removed from config/CLI/docs/tests.
• Snapshot builder behavior unchanged for default path.