test(tempo): fuzz transaction serialization

[brendanjryan]

Motivation

Tempo transaction envelopes combine nested calls, configurable fees, access lists, parallel nonces, validity windows, and multiple token representations. Example-based cases cover individual shapes but do not exercise their cross-product or canonical encoding behavior. This change is stacked on #4974.

Summary

• add fast-check generators for canonical Tempo transaction envelopes
• compare viem serialization byte-for-byte with the ox reference codec
• verify serialize-deserialize-serialize stability across generated envelopes
• reject generated 0x76 and 0x78 envelopes with invalid RLP field counts
• include transaction envelopes in the Tempo fuzzing runbook

Key design considerations

• keep codec properties pure and deterministic for high CI iteration counts
• generate only protocol-valid cross-field combinations so shrinking preserves useful failures
• cover boundary values including zero and maximum-width integer fields

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[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@​fast-check/​vitest@​0.4.1
	prool@​0.2.14
	fast-check@​4.9.0

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npm i https://pkg.pr.new/viem@4977

commit: ea738bc