refactor: execute PoL in normal transaction pipeline

[NikhilSharmaWe]

Closes #64

Summary

PoL was previously executed in apply_pre_execution_changes, then handled again during import with dummy results and commit skips, and injected into the block during assembly. That required extra workarounds, including BerachainBlockBuilder and fix_pol_senders (#129).

This PR moves PoL into the normal transaction pipeline:

• Execute PoL as tx #0 via execute_transaction during payload building
• Remove PoL special-casing from the executor
• Stop injecting PoL in the assembler; only validate it is present at index 0
• Remove BerachainBlockBuilder and fix_pol_senders
• Zero gas for PoL on revert/halt in transact_raw

Test plan

• cargo build
• cargo +nightly clippy --all-targets --all-features -- -D warnings
• cargo nextest run --locked

Summary by CodeRabbit

• New Features

  • Prague1 blocks now process Proof-of-Liquidity (PoL) through the standard transaction execution flow.
  • When Prague1 is active, block production requires non-empty receipts and validates that the first transaction is the PoL transaction.

• Bug Fixes

  • PoL transaction execution now correctly reports zero gas usage even when execution reverts or halts.
  • Improved PoL validation and error reporting, including clearer failures for PoL before Prague1 activation and when the required proposer information is missing.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: f6b76101-1f5d-4237-b8df-c01258964054

📥 Commits

Reviewing files that changed from the base of the PR and between 8b4bbe4 and 68bfb24.

📒 Files selected for processing (1)

• src/transaction/pol.rs

✅ Files skipped from review due to trivial changes (1)

• src/transaction/pol.rs

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📝 Walkthrough

Walkthrough

PoL execution now happens in the payload builder as transaction #0 after Prague1 activation. The executor, EVM accounting, and assembler were updated to treat PoL consistently, and the Berachain block-builder wrapper was removed.

Changes

PoL transaction execution relocation

Layer / File(s)	Summary
Payload builder executes PoL as tx #0 src/engine/builder.rs	default_berachain_payload now checks Prague1 activation, requires prev_proposer_pubkey, builds a PoL transaction with the current block number and base fee, and executes it signed by SYSTEM_ADDRESS.
Executor and POL accounting updates src/evm/mod.rs, src/node/evm/executor.rs, src/transaction/pol.rs	POL Revert and Halt results now report zero gas, POL-specific execution shortcuts are removed from the node executor, proposer pubkey validation is added to pre-execution changes, and SYSTEM_ADDRESS imports now come from alloy_eips::eip7002.
Assembler validates PoL placement and block builder wiring src/node/evm/assembler.rs, src/node/evm/config.rs, src/node/evm/mod.rs	assemble_block now validates that transaction 0 is a Berachain transaction instead of injecting PoL, create_block_builder returns a plain BasicBlockBuilder, and the internal builder module declaration is removed.
POL error variant update src/node/evm/error.rs	The POL error set replaces the invalid-type variant with a before-Prague1 variant.

Estimated code review effort: 4 (Complex) | ~60 minutes

Possibly related PRs

• berachain/bera-reth#219: Reverses the BerachainBlockBuilder wrapper behavior that this PR removes from the block-builder path.
• berachain/bera-reth#145: Also changes POL execution handling in src/evm/mod.rs.
• berachain/bera-reth#218: Also changes PoL execution and commit behavior in src/node/evm/executor.rs.

Suggested reviewers: fridrik01

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title is concise and accurately describes the main change: executing PoL through the normal transaction pipeline.
Linked Issues check	✅ Passed	The PR satisfies #64 by moving PoL execution into the core transaction path and updating block builder behavior accordingly.
Out of Scope Changes check	✅ Passed	No clearly unrelated changes are present; the edits support the PoL execution refactor and associated builder/executor updates.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Copilot]

Pull request overview

Refactors Proof-of-Liquidity (PoL) execution so it runs as the first transaction (tx #0) in the normal block transaction pipeline during payload building, eliminating prior special-casing and assembly-time injection workarounds.

Changes:

• Executes PoL as tx #0 during payload building and removes executor-side PoL bypass/skip logic.
• Updates block assembly to validate PoL presence at index 0 (post-Prague1) instead of injecting it.
• Removes the custom block builder wrapper previously used to patch sender/transaction mismatches from PoL injection, and ensures PoL gas-used is zero even on revert/halt.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/node/evm/mod.rs	Removes the now-unneeded builder module wiring.
src/node/evm/executor.rs	Drops PoL system-call execution + receipt forging and removes PoL commit-skips/dummy results.
src/node/evm/error.rs	Removes an error variant tied to the deleted PoL execution path.
src/node/evm/config.rs	Stops wrapping BasicBlockBuilder with BerachainBlockBuilder; returns the basic builder directly.
src/node/evm/builder.rs	Deletes the PoL injection sender-fix wrapper and its tests.
src/node/evm/assembler.rs	Stops injecting PoL; validates PoL is present at index 0 post-Prague1.
src/evm/mod.rs	Forces PoL gas used to 0 even on revert/halt in the PoL execution path.
src/engine/builder.rs	Executes PoL as tx #0 during payload building (post-Prague1).

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[NikhilSharmaWe]

@calbera PTAL, thanks