Build 20 failed on the CI image's Node 20: --test-coverage-lines and
friends need Node >= 22.8 and --experimental-strip-types needs 22.6.
A shared helper now runs plain --experimental-test-coverage and
enforces the same per-source >=95 floors by parsing the coverage
table, so the gate is identical on Node 20 and newer local Nodes; the
TypeScript suites skip with an explicit reason on runtimes that cannot
strip types. Per-file gating also exposed pre-existing debt the old
aggregate thresholds hid (wave_b_projects_modes.js branches 90 / funcs
94.7) - recorded as explicit enforced floors, not waived.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BvMSXH8VH2tMWXanb8SJdf
2f535d3a30