fix(docs): restore README.adoc as canonical entry point, remove README.md #523

Job	Run time
governance / Security policy checks	8s
governance / Guix primary / Nix fallback policy	3s
governance / Well-Known (RFC 9116 + RSR)	7s
governance / Check Workflow Staleness	7s
governance / Language / package anti-pattern policy	13s
governance / Licence consistency	6s
governance / Code quality + docs	10s
governance / Workflow security linter	5s
governance / Trusted-base reduction policy	7s
governance / Validate Hypatia Baseline	-1s
	1m 5s

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