fix: encode genesis transaction IDs as bytes32

[littlehand26]

Summary

• encode synthetic genesis transaction IDs using the pipeline v0.0.69 bytes32 layout
• propagate canonical transaction IDs into genesis traces and their derived IDs
• lock exact ID vectors and the Arc mainnet genesis validation hash (356679)

Scope

This changes only block 0 BlockFile IDs and Validation. Header, StateDiff, canonical block data, and blocks H >= 1 are unchanged.

A deployment must use a new immutable pipeline version. The existing 88aa7766 prefix must remain read-only.

Validation

• rustup run 1.91.1 cargo test --locked -p debank-rpc --lib (41 passed)
• ./scripts/test-debank-blockfile.sh (15 e2e tests passed; 56 total with unit tests)
• rustup run 1.91.1 cargo clippy --locked -p debank-rpc --all-targets --all-features -- -D warnings
• rustup run 1.91.1 cargo fmt --all -- --check
• git diff --check

[littlehand26]

Stack follow-up: fixture exporter #7 is now based directly on this PR and has passed two independent fixture captures plus provenance/determinism checks. Merge #6 with a merge commit before retargeting #7.

[littlehand26]

Superseded by #9. The canonical bytes32 genesis transaction IDs and golden tests were ported in f9525a5 and are present on debank; the v0.8.0 implementation also uses the corrected EIP-55 ordering. Closing the old stacked PR, not reverting its fix. Branch and review history are retained.