Light mode: audit and fix styling consistency across configuration screens

[zindello]

Summary

Light mode styling has some inconsistencies across the configuration tab panels. These need to be audited and brought into line with the design system.

Known issues

• Some configuration screens appear to have differing visual styles (spacing, card treatments, input styling) compared to others — needs a full sweep across all config tabs
• The author noted that buttons and snack bars have lost padding that has crept in as a regression — this affects the general UI in light mode particularly

Scope

• Audit all configuration tab panels (src/components/configuration/) in light mode
• Check button padding/sizing is consistent with the design system globals (btn-*, modal-btn-*)
• Check snack bar / notification spacing
• Ensure cfg-section, cfg-card, cfg-input, cfg-select utility classes are used consistently
• Verify no raw hex values or Tailwind colour literals have been introduced

Notes

Dark mode appearance is not the primary concern here — focus is light mode parity and padding regressions.