Unify colour handling in selects and buttons - #140

Description

The Button Colour picker on the panel create/edit pages listed Blue / Grey / Green / Red as plain text — you had to already know Discord's palette to pick correctly. Each option now shows its actual colour, plus the same treatment everywhere else it fits.

Select already supported a per-option color; the options simply never passed one, so no new component was needed.

Changes

Button Colour — options carry their colour, shared from a new constants/buttonStyles.ts so the picker and the live PanelPreview read from one table.

⚠️ Visible change: the preview palette moves from Discord's old hover shades (#4752c4 / #4f545c / #2d7d46 / #a12d2f) to its current button colours (#5865F2 / #4E5058 / #248046 / #DA373C), so preview buttons now match what Discord actually renders. discord/container/Button.tsx paints the background inline rather than via a Tailwind class — a class name built from a map is never generated at build time.

Dots that never worked — MultiSelect expected abc123 for its dot but #abc123 for its chip tint, so one was always invalid CSS. Both selects now normalise the value:

• a role coloured 0x00b0f4 produced #b0f4 (invalid, no dot) → now #00b0f4
• an uncoloured role produced #0 → now Discord's default grey #99AAB5 instead of black
• the selected-chip tint renders for the first time, as color-mix(… 20%) matching LabelBadge

New swatches — the access-control "Add Role" picker (dropdown and the added-role list), the setup wizard's Teams step (colour was being stripped in Setup.tsx), and the Guild Settings / Tickets / Transcripts panel pickers.

Status dots on the four filters whose values already have a badge colour: affiliate status, gallery type (×2), bot-staff tier. GALLERY_TYPE_BADGES is now the single source — the duplicate map in GalleryCard.tsx and both local TYPE_OPTIONS copies are gone.

intToColour / colourToInt were defined three times; both now live in lib/colour.ts.

Type of Change

• Bug fix
• New feature
• Breaking change
• Improvement

Checklist

• My code follows the style of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works