Split root CLAUDE.md into 19 per-directory files scoped to their source area.
Roll v0 history into docs/ARCHIVE.md; retire CONTEXT.md, CONTEXT-ARCHIVE.md,
PLAN.md, COMPLETED.md. Move plan docs under docs/. Rescue 9 live deferrals
into docs/TODO.md.
Adds the two missing removal capabilities: sample-level remove (Phase B
point B5, index-only) and the prune file-lifecycle path (new Phase R, the
sole file-deleting op), resolving the dangling capture/prune reference.
Adds CONTEXT.md spec, PLAN.md points, and a product note; surfaces forks
R-A..R-E for decision.