fix: reduce load on RPC nodes

[shoom3301]

Summary

Fix A — apps/cowswap-frontend/.../usePendingTransactionsContext.ts + FinalizeTxUpdater/index.tsx:
Hook now takes hasPendingTxs: boolean; when no pending txs exist, it returns null without calling getTransactionCount. FinalizeTxUpdater passes transactions.length > 0. Behavior unchanged for users with pending txs; eliminates the nonce call for every connected user every block.

Fix B + C — libs/wallet/src/wagmi/config.ts:
Added a single VIEM_CLIENT_TUNING constant spread into both the Safe-iframe createConfig and the WagmiAdapter constructor:

• batch.multicall: { wait: 130, batchSize: 30_000 } — auto-aggregates singular useReadContract calls into multicall3
• pollingInterval: 12_000 — overrides viem's 4 s default

I've checked the version before Viem migration, and we were making eth_call with ~24kb payload. Alchemy recommends keeping the payload less then 100kb, so 30kb looks a good trade-off here.

Expected impact

• eth_blockNumber: ~3× reduction (4 s → 12 s polling)
• eth_getTransactionCount: ~10–20× reduction (gated on pending txs; most users have none)
• eth_call: ~5–10× reduction (singular useReadContract calls now batched). Won't reach the full 20× without also addressing D (overlapping balance/allowance pollers).

To Test

1. Balances loading
2. On-chain tx finalizing: mined/failed/replaced (approve, wrap/uwrap, eth-flow)

Summary by CodeRabbit

• Performance
  • Optimized pending transaction detection logic for improved efficiency.
  • Enhanced wallet configuration with improved multicall batching and polling intervals for better network communication.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 71c12cda-f5bc-4661-8620-4020089277e7

📥 Commits

Reviewing files that changed from the base of the PR and between 6a26349 and aaac8e3.

📒 Files selected for processing (3)

• apps/cowswap-frontend/src/modules/onchainTransactions/updaters/FinalizeTxUpdater/hooks/usePendingTransactionsContext.ts
• apps/cowswap-frontend/src/modules/onchainTransactions/updaters/FinalizeTxUpdater/index.tsx
• libs/wallet/src/wagmi/config.ts

---

Walkthrough

This PR introduces conditional optimization for pending transaction context evaluation and configures viem client batching behavior. The pending transactions hook now skips processing when no transactions are pending, and wallet configuration now includes explicit tuning for multicall batching and polling intervals across both Safe and standard configurations.

Changes

Transaction Finalization and Configuration

Layer / File(s)	Summary
Pending transaction context optimization apps/cowswap-frontend/src/modules/onchainTransactions/updaters/FinalizeTxUpdater/hooks/usePendingTransactionsContext.ts, apps/cowswap-frontend/src/modules/onchainTransactions/updaters/FinalizeTxUpdater/index.tsx	Hook signature updated to accept hasPendingTxs: boolean; early return logic now checks this flag to skip async computation when no transactions exist; dependency array updated; call site passes transactions.length > 0.
Viem client tuning configuration libs/wallet/src/wagmi/config.ts	VIEM_CLIENT_TUNING object added to configure multicall batching parameters (batch.multicall.multicall.wait, batchSize) and polling interval; applied to both Safe-iframe and standard wallet configuration paths; SUPPORTED_REOWN_NETWORKS type cast removed in Safe path.

🎯 2 (Simple) | ⏱️ ~12 minutes

🐰 A rabbit hops through transactions with newfound grace,
Skipping empty lists at a brisk pace,
While viem's batches align to their tune,
Polling steady beneath the blockchain moon!
Configuration harmonized, efficiency blooms—
The transaction gardens fill waiting rooms. 🌙✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'fix: reduce load on RPC nodes' directly and concisely summarizes the main objective of the changeset, which involves reducing RPC calls through three targeted optimizations.
Description check	✅ Passed	The description covers all required template sections: Summary with detailed explanations of changes, testing steps, and background context on performance impact.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/rpc-node-consumption

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[limitofzero]

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[elena-zh]

Tested on all chains except ink where I was not able to get a qupte: works fine with Rabby and MM+WC.
As for Safe, was not able to fully test it because of the known issue, so txs are not finalized. But balances were updated there (tested on Base)