The .bt-* rules (bar, grid, group, hist, name, procs, row, val) leave the stylesheet #4616

No markup under src/ draws the eight .bt-* classes any more; only the rules remain.

Done:

• [ ] no rule for the eight .bt-* classes remains in src/web/style/content.ts
• [ ] the eight .bt-* classes is gone from docs/DESIGN.md §5d
• [ ] grep -rn for each name under src/ and test/ finds nothing (a test that asserts the old name is updated to assert its absence)
• [ ] the pages that once drew them render unchanged

Run bun scripts/design-lint.ts and bun test test/design-lint.test.ts before pushing; where counts fall, lower docs/design/baseline.json in the same pull. Replaces #4167: the crew's two tries went red on tests this change does not touch (those are planned separately), so keep the diff to the files named.

Parked by the crew: @mason's run ended without a pull: the pull closed

Parked by the crew: @mason's run ended without a pull: the pull closed

Parked twice since a person last spoke here, so it is the planner's now. Every reason:

1. @mason's run ended without a pull: the pull closed
2. @mason's run ended without a pull: the pull closed

The planner splits it, replaces it with a fresh issue, or defers it; a person can also say what to try. Nothing starts here until then, and the board lists it.

Dropped: already on main in f8970686 (#5269). The eight .bt-* rules left the stylesheet there, and test/system-btop.test.ts asserts that none remains in markup or stylesheet. Both runs closed their pull because there was nothing left to change.