[kbuffardi]

Summary

• Improve active and inactive selection contrast for monochrome-light and monochrome-dark.
• Keep Monaco and xterm selection colors synchronized within each theme and state.
• Add WCAG AA contrast assertions for configured selections and rendered Monaco/xterm smoke coverage.

Verification

• npm run lint
• npm run build
• npm run test:e2e — 232 passing
• node scripts/smoke-browser.mjs chrome — unable to complete in this environment; the harness hung during browser startup/runtime verification and was stopped.

The five existing non-monochrome themes were not changed.

Closes #121

[kbuffardi]

Implementation correction

@kbuffardi reported:

the current implementation is incorrect so the new tests must be wrong as well. In both monochrome themes, the background selection is the same color as the text so there is NO contrast.

Root cause: Monaco applied the configured selection background but retained the token foreground inside selected text. The previous smoke hook created a synthetic span, so it did not prove the actual Monaco selection rendering.

The PR now:

• explicitly overrides Monaco .selected-text foregrounds for the two monochrome themes;
• probes a real Monaco model selection in the smoke hook; and
• retains WCAG AA checks for active/inactive Monaco and xterm selections.

Verification passed: lint, production build, and 234 E2E tests.

[kbuffardi]

Monaco overlay correction

@kbuffardi reported:

active selected text has the same text color as background color; when another pane is focused on, then there is at least some contrast but I'm still not sure if it is proper contrast.

The active-state screenshots showed that Monaco draws selection backgrounds in an overlay separate from source-code text spans. The previous selected-text CSS targeted the overlay and could not change the glyph color.

The PR now removes that ineffective override and uses WCAG AA grayscale overlay backgrounds that contrast with Monaco's actual code foreground:

• Monochrome Light: black on #999999 (active) and #bbbbbb (inactive).
• Monochrome Dark: white on #555555 (active) and #707070 (inactive).

The smoke hook now reads the real selection overlay background and the rendered source span color independently. Lint, production build, and 234 E2E tests passed.