Claude Code engine, image viewer, colour tags, checks per turn and more

- Claude Code as an engine: chats on a "claude-code/<alias>" model run through
  the claude CLI (stream-json); tool approvals go through our permission
  system. Sign in from the web UI (URL + pasted code), CLI version and update
  from Settings; the Docker image contains the CLI.
- Small models (8k context) for side tasks: input is cut to the model's
  context window; one-line chat status, "What does this do?" on approvals,
  "Plan as automation" (job draft from a chat).
- Mobile: top bar no longer widens the page, image viewer (zoom, swipe, mark
  up, use in message), jump to previous own message, message menu, time under
  every message.
- Approvals: push actions (allow/reject), "always allow in this project"
  (never for dangerous commands) with revoke.
- Per turn: changed files with diffs and rollback; project check command with
  a green/red badge and "let the agent fix it".
- Colour tags for chats in the colours of the active theme.
- Project defaults for new chats, project page (timeline), offline queue.

Tested in a throwaway container with a mock model (8k small model): 26 API
checks passed (permissions, diffs, checks, defaults, job draft, side-task
budget, Claude Code status/login URL, unsigned-in chat).

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

web/src/components/Icon.tsx

@@ -34,6 +34,7 @@ const P: Record<string, ReactNode> = {
   download: <path d="M12 4v11M7 10l5 5 5-5M5 20h14" />,
   compact: <path d="M8 4l4 4 4-4M8 20l4-4 4 4M4 12h16" />,
   trash: <path d="M4 7h16M9 7V4h6v3M6 7l1 13h10l1-13M10 11v6M14 11v6" />,
+  reply: <path d="M9 7 4 12l5 5M4 12h9a7 7 0 0 1 7 7" />,
   edit: <path d="M4 20h4L19 9l-4-4L4 16v4ZM13.5 6.5l4 4" />,
   undo: <path d="M9 14 4 9l5-5M4 9h10a6 6 0 0 1 0 12h-3" />,
   clip: <path d="m20 11-8.5 8.5a5 5 0 0 1-7-7L13 4a3.5 3.5 0 0 1 5 5l-8.5 8.5a2 2 0 0 1-3-3L14 7" />,