Build trace histogram tool (reproduce traceRes.txt)

[tjayrush]

Summary

Create a standalone Go tool (or example) that walks blocks and counts traces per transaction, reproducing the data from the old C++ `traceCounter` that generated `traceRes.txt` for the DDoS article.

Implementation

• Walk blocks via `GetBlockHeaderByNumber` → `LightBlock.Transactions` (list of tx hashes)
• Call `GetTracesCount` per transaction (binary search, ~2*log2(N) RPC calls each)
• Accumulate results into a grid (e.g., 251 block ranges × 100 trace count buckets)
• Output CSV or JSON suitable for chart generation

Context

• `GetTracesCount` is implemented in `chifra/pkg/rpc/get_trace_count.go`
• The old C++ tool scanned the DDoS era (blocks ~2.2M–2.7M) and produced histogram data
• Could live in `examples/` as a new example project