docs: post-PR-136 narrative refresh (CHANGELOG + EXPLAINME + MAP + README) #234

Job	Run time
governance / Code quality + docs	15s
governance / Security policy checks	4s
governance / Licence consistency	8s
governance / Well-Known (RFC 9116 + RSR)	6s
governance / Validate Hypatia baseline	3s
governance / Guix primary / Nix fallback policy	6s
governance / Language / package anti-pattern policy	8s
governance / Trusted-base reduction policy	7s
governance / Workflow security linter	5s
	1m 2s

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