[biast12]

RM-348

Description

Every embed colour picker gets an × that sets the colour to No colour (Discord's default bar). The API uses null for no colour, and 0 / #000000 is black.

• Pickers: panel, welcome message, multi-panel, tag, KB article, setup wizard, out-of-hours, and Success/Failure. ColourSelect gets an opt-in nullable / clearable variant.
• Previews draw Discord's default border for no colour, and panel colour dots are hidden.
• Backend: colour fields are pointers (null ↔ NULL). Panel and out-of-hours colours are range-checked, and settings colours accept null. Panel, multi-panel and gallery payloads leave color out for no colour.
• Also fixed:
  • the KB editor no longer turns a missing colour into blurple;
  • the setup wizard no longer turns black into blurple;
  • GalleryCard no longer crashes on a null colour;
  • transcripts now show black embeds and container accents.

Needs:
TicketsBot-cloud/gdl#19
TicketsBot-cloud/database#49
TicketsBot-cloud/worker#162

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

[BenHall-1]

Ready for merge on db & gdl and bump :)