[FEATURE] Color-coded agent display in multi-agent view

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When running multiple agents in parallel, the CLI displays all agents in the same color:

Running 3 agents… (ctrl+o to expand)
├─ backend-dev (Implement feature A) · 23 tool uses · 66.1k tokens
├─ reviewer (Review changes) · 18 tool uses · 45.2k tokens
└─ researcher (Investigate options) · 12 tool uses · 30.1k tokens

With 3+ agents running simultaneously, it's hard to quickly scan and distinguish which agent is doing what. In multi-agent orchestration workflows, I frequently glance at this view to check progress — same-color text slows down visual parsing.

Proposed Solution

Color-code agent names by subagent_type so each agent type has a distinct visual identity:

• Assign colors automatically based on agent name hash (no config needed, just works)
• Or allow user configuration in settings.json (e.g., "agentColors": {"backend-dev": "blue"})
• Fallback to default terminal color if not configured

Alternative Solutions

• Currently I read the agent name text to distinguish them, which is slower than color scanning
• Terminal-level theming doesn't help since the CLI controls the output colors, not the terminal

Priority

Medium - Would be very helpful

Feature Category

Interactive mode (TUI)

Use Case Example

1. I orchestrate multi-agent workflows with 3-5 specialized agents running in parallel (research, implementation, review)
2. I glance at the agent status view frequently to check which agent is done
3. With color-coding, I could instantly spot "the blue one (backend) is done, the purple one (researcher) is still working" without reading text
4. This would save cognitive load during complex orchestration sessions

Additional Context

The agent name hash approach would require zero configuration — just deterministically map each unique subagent_type string to one of 6-8 ANSI colors. This is a common pattern in logging libraries (e.g., debug npm package uses this exact approach).