BUG: Dark mode theme missing on Edit Card modal, Edit Column modal, and Filter panel

[Chris0Jeky]

Summary

Three surfaces render with white/light backgrounds against the dark workspace shell: the Edit Card modal, the Edit Column modal, and the Filter Cards panel. These are dark-mode theming regressions.

Affected Surfaces

1. Edit Card modal — white background when opening any card
2. Edit Column modal — white background when editing a column
3. Filter Cards panel (opened with f key) — white background

Reproduction

1. Use app in dark mode (the default workspace shell)
2. Open any card modal, or click the column edit icon, or press f for filter
3. Observe white/light background breaking the visual context

Expected

All modals/panels use dark-mode tokens (--td-* design tokens, bg-td-surface class) consistent with the board canvas.

Fix

Audit the three components for missing dark-mode token application. Apply the same bg-td-surface / dark token classes used on the board canvas and other correctly-styled modals.

Priority

P1 — dark mode regression affecting core surfaces

Discovered in manual testing session 2026-03-29. See docs/analysis/2026-03-29_manual_testing_consolidated_findings.md (BUG-H2, BUG-H3, BUG-H4).