feat(p2p): New transaction pool implementation

[PhilWindle]

Summary

• Introduces a new transaction pool implementation (TxPoolV2) with explicit state management
• Transactions flow through states: pending → protected → mined → deleted
• Implements a pluggable eviction rules system for managing pool size and transaction validity
• Adds transaction validation using pendingTxValidator before adding to pending pool
• Includes archive support for finalized transactions

Key Components

• State Management: Transactions have explicit states (pending, protected, mined) with clear transitions
• Eviction Rules: Modular rules for nullifier conflicts, fee payer balance limits, pool size limits, and post-reorg validation
• Pre-add Rules: Validation before adding transactions (duplicates, nullifier conflicts, fee payer balance)
• Archive: Optional archiving of finalized transactions for historical queries

Test Coverage

• 131 unit tests covering all state transitions and edge cases
• Compatibility tests ensuring feature parity with existing pool
• Benchmarks for performance measurement (addPendingTxs, canAddPendingTx, handlePrunedBlocks, etc.)

Test plan

• Unit tests pass: yarn test src/mem_pools/tx_pool_v2/tx_pool_v2.test.ts (131 tests)
• Compatibility tests pass: yarn test src/mem_pools/tx_pool_v2/tx_pool_v2.compat.test.ts (25 tests)
• Eviction rule tests pass: yarn test src/mem_pools/tx_pool_v2/eviction/ (86 tests)
• Benchmarks run: yarn test src/mem_pools/tx_pool_v2/tx_pool_v2_bench.test.ts

🤖 Generated with Claude Code

[PhilWindle]

The only place we hydrate transactions from the DB, except when requested over the API. Will remove this in a follow up PR when we refactor transaction validation.

[AztecBot]

Flakey Tests

🤖 says: This CI run detected 2 tests that failed, but were tolerated due to a .test_patterns.yml entry.

\033FLAKED\033 (8;;http://ci.aztec-labs.com/90225d9a219310b6�90225d9a219310b68;;�):  yarn-project/end-to-end/scripts/run_test.sh simple src/e2e_bot.test.ts (259s) (code: 1) (\033Phil Windle\033: More tests)
\033FLAKED\033 (8;;http://ci.aztec-labs.com/a2d66d33b1d6a800�a2d66d33b1d6a8008;;�):  yarn-project/end-to-end/scripts/run_test.sh simple src/e2e_p2p/reqresp/reqresp.test.ts (337s) (code: 1) group:e2e-p2p-epoch-flakes (\033Phil Windle\033: More tests)