ci(spark): adopt estate SPARK Theatre Gate (#135) #150

Job	Run time
governance / Guix primary / Nix fallback policy	3s
governance / Code quality + docs	17s
governance / Security policy checks	4s
governance / Well-Known (RFC 9116 + RSR)	8s
governance / Workflow security linter	6s
governance / Language / package anti-pattern policy	4s
	42s

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