[contursofran]

Fixes #741

The checks dot is gone from PR and issue chips and from the board's PR cell. The Octicon's color now shows the state. It uses content tokens only, so both themes work (D288; it replaces that part of D286).

State	Token
PR checks failed	content-failed
PR checks running	content-running
PR checks passed / open	content-done
PR draft	ink-48
PR merged	content-link (the palette has no purple)
PR closed	ink-48 (a red would read as failed)
Issue open / closed	content-done / content-link

Tooltips and labels still name the state.

Pre-check

1. Tests: TestGitHubColor (new) failed with a changed color mapping; TestChipIcon checks the width without a dot.
2. Plan: done. Deviation: merged and closed issue use content-link, as no purple token exists.
3. Contract: n/a.
4. Up to date with main; no open PR touches chips.go.
5. Diff read; no leftovers.
6. Issue acceptance: all done.
7. Duties: the checks state is still in the icon color, the tooltip and the label.
8. Sheet: scripts/sheet.sh ChatViewChips, dark and light, checked chip by chip.