Chat bubbles, icons for chats, more vivid and distinct colour tags

- Bubbles: own messages right-aligned in their own colour, agent answers left.
- Chat icons (22, validated on the server), shown in list, top bar, project page.
- Colour tags: eight fixed hues (new: pink) with theme-matched lightness and the
  highest chroma sRGB allows; stronger background tint.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

web/src/i18n/en.ts

@@ -400,6 +400,8 @@ export const en = {
   "color.aqua": "Teal",
   "color.blue": "Blue",
   "color.purple": "Purple",
+  "color.pink": "Pink",
+  "icon.label": "Icon of this chat",
   "claude.title": "Claude Code",
   "claude.intro": "Chats with a \"Claude Code\" model are run by the Claude Code CLI on the server – with your Claude subscription or Anthropic Console account. Sign in here once; approvals, push and the sandbox work as usual.",
   "claude.notInstalled": "Claude Code is not installed on the server.",