add tx_hash ordering strategy for deterministic numerical block ordering

[vbuilder69420]

Closes #20

Description

Adds a new TxHash ordering strategy (sorting = "tx_hash" in config) that sorts SimulatedOrders numerically by their identifier's fixed_bytes() (B256):

• Mempool txs → sorted by transaction hash
• Bundles → sorted by bundle UUID bytes zero-padded to 32 bytes

This produces a fully deterministic, profit-agnostic block ordering, useful for the cases described in the issue.

Changes

File	Change
building/block_orders/order_priority.rs	Add OrderTxHashCmp + OrderTxHashPriority via macro + unit test
building/mod.rs	Add TxHash variant to Sorting enum with constant, FromStr, Display
live_builder/config.rs	Import + wire up Sorting::TxHash in both match blocks

Usage

[[builders]]
name = "numerical"
sorting = "tx_hash"

Test Results

• cargo check ✅
• cargo clippy --workspace --features="" -- -D warnings ✅
• New unit test: order_priority::test::tx_hash_ordering — verifies lower hash ID sorts before higher hash ID

Safety

No safety-critical paths touched. Pure ordering strategy addition.