refactor(test): add gossip screening for fees and fix breakpoint test

[erhant]

🎯 Purpose

The #801 (fees) merge tripled nextest wall time (525s → 1530s; the unit-tests job went 24.5 min → ~53 min and started timing out): every charged transaction now runs up to three zkVM guest emulations (reserve → action → refund) and dev mode does not help (as it skips proving, not execution).

This PR takes the free wins from that investigation (kudos to @moudyellaz ):

1. A test put_block_stores_breakpoint_in_same_batch that never needed settleable blocks was paying for ~795 guest executions.

2. The block builder ran a full scratch-clone settlement (all three guest runs) on every mempool candidate before discovering it could not pay, and gossiped transactions entered the mempool with no fee screening at all.

⚙️ Approach

• put_block_stores_breakpoint_in_same_batch (storage): chain produce_dummy_blocks instead of signed, settled transfer blocks — put_block never settles, so the breakpoint-batch assertions are unchanged and the test goes from ~795 guest executions to zero (327s → seconds in CI)
• Builder: run the cheap fees::screen (static checks + one balance read, no clone, no execution) on every User/Gossip candidate before the scratch clone and settlement, so junk is dropped for a balance read instead of three guest runs
• Gossip ingest: screen a peer's transaction through the same fees::screen before it takes a mempool slot, via a new screen-only ScreenTransaction executor message — one admission door for RPC and gossip. Deliberately advisory: the verdict never affects gossipsub mesh acceptance (admission is priced off the local head state, which drifts, so peers legitimately disagree), and a screened-out tx stays un-seen so a rebroadcast can retry once e.g. its payer is funded. Closes fees: screen gossip-ingested transactions through fee admission #797
• Document that MAX_GAS_EXEC caps action-phase gas only; the reserve/refund invocations and the fee/clock tail run unmetered as a bounded per-transaction constant

🧪 How to Test

# The reverted test, now sub-second:
RISC0_DEV_MODE=1 cargo test -p storage put_block_stores_breakpoint_in_same_batch

# Gossip + builder paths (gossip tests use the new admit-all screen):
RISC0_DEV_MODE=1 cargo test -p sequencer_core --all-features gossip
RISC0_DEV_MODE=1 cargo test -p sequencer_core --all-features tests::

🔗 Dependencies

None

🔜 Future Work

None

📋 PR Completion Checklist

• Complete PR description
• Implement the core functionality
• Add/update tests
• Add/update documentation and inline comments

[Copilot]

🟡 Changes recommended

The new IngestScreen type currently won’t compile due to anyhow::Result generic misuse, and the gossip driver’s inline async screening also introduces a potential responsiveness/DoS concern that should be addressed.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR reduces unit-test CI wall time and tightens fee-admission hygiene by introducing a cheap fee screen earlier in both the block builder and the gossip-ingest path, plus refactoring an expensive storage breakpoint test to avoid unnecessary zkVM guest execution.

Changes:

• Refactors put_block_stores_breakpoint_in_same_batch to use dummy (unsettleable) blocks, eliminating zkVM execution in that test.
• Adds a fee-admission screen (fees::screen) before scratch-clone settlement in the sequencer’s mempool candidate path.
• Adds an advisory gossip-ingest fee screen via a new ScreenTransaction executor message and an IngestScreen hook in GossipNetwork.

File summaries

File	Description
lez/storage/src/indexer/tests.rs	Refactors breakpoint test to chain dummy blocks and avoid zkVM guest runs.
lez/sequencer/service/src/lib.rs	Wires a gossip-ingest fee screen via the executor actor before mempool admission.
lez/sequencer/core/src/lib.rs	Runs fees::screen before scratch-clone settlement for User/Gossip candidates.
lez/sequencer/core/src/gossip/tests.rs	Updates gossip tests to pass an admit-all ingest screen.
lez/sequencer/core/src/gossip/network.rs	Adds IngestScreen, applies it during gossip ingest, and makes swarm event handling async.
lez/sequencer/core/src/gossip/mod.rs	Re-exports IngestScreen and admit_all_screen.
lez/sequencer/actors/executor/src/protocol.rs	Introduces ScreenTransaction message for screen-only admission checks.
lez/sequencer/actors/executor/src/actor.rs	Implements handler for ScreenTransaction to run fees::screen on head state.
lez/programs/fee/core/src/market.rs	Documents that MAX_GAS_EXEC caps action-phase gas only (reserve/refund + tails unmetered).

Review details

• Files reviewed: 9/9 changed files
• Comments generated: 3
• Review effort level: Lite

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[Pravdyvy]

lgtm

[erhant]

#831 must be merged BEFORE this one

[Arjentix]

LGTM, looking forward to make gossiper a separate actor

[moudyellaz]

lgtm, thanks!