feat: EchoResidueCell — Agda mirror of 007's Holding/Spent once-only discipline #469

Job	Run time
governance / Language / package anti-pattern policy	8s
governance / Trusted-base reduction policy	8s
governance / Security policy checks	4s
governance / Well-Known (RFC 9116 + RSR)	5s
governance / Licence consistency	7s
governance / Validate Hypatia baseline	5s
governance / Code quality + docs	14s
governance / Workflow security linter	4s
governance / Guix primary / Nix fallback policy	4s
	59s

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