Groups sessions by their opening block (whitespace/ANSI-normalized, hashed
over the first 2 KB) and flags a block of at least 1.5 KB that opens five or
more sessions. Class nudge: CodeBurn will not move the user's own text into
CLAUDE.md, so the fix asks Claude to give the block a permanent home. Only
the repeats count as savings, sized from the block's bytes because provider
usage is per API call and cannot isolate the paste. The opener comes from
the session scan that already runs, so nothing extra is read.
Adds docs/optimize.md (what optimize scans, the three classes, the exact
files --apply may touch plus undo, measured vs estimated, the health
grade bands, the --yes CLAUDE.md guardrail), links it from the README
waste section, and corrects the detector count in docs/architecture.md
(14 -> 19).
