Archive 21 implemented triplets whose shipped decisions are complete and
whose bodies no longer guide future work (one-off UI chrome, generator
applications whose scripts are self-explanatory, superseded implementation
detail, process history owned by current contracts/skills). Delete 4
rejected triplets whose premises are obsolete: the DeepReadonly proposal
(dev-invariants note now carries the alternative inline), the collapse
tool-owned presentation proposal (superseded by the shipped render-intent
union), retire-mid-turn-steering (steering is now load-bearing across
plan-mode/apiproxy/TUI), and single-session-ACP (automation-only ACP
resolved the question; multi-session isolation is pinned by tests).
Repair every inbound link: retarget intentional historical citations to
archived paths, replace decision-current citations with the surviving
authority, and fix the stale example-execute-over-tsx pointer in
pnpm-workspace.yaml. Re-record pairing sidecars and seal the archive
manifest (append-only; existing seals unchanged).
