Allow customization of conversation titles via CLAUDE.md or settings

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

I'd like to influence how sidebar conversation titles are generated. Currently, titles are auto-generated, but I want more control over the format to make my sidebar easier to scan visually.

Specifically, I want every conversation title to start with a relevant emoji (e.g., "🔧 Fix auth bug", "📊 Commission audit") to make finding conversations faster and more intuitive.

Proposed Solution

Allow users to customize conversation title generation through one of these approaches:

1. CLAUDE.md instruction: Respect instructions like "Prefix all conversation titles with a relevant emoji"
2. settings.json field: Add a titleFormat or titlePrefix field that users can configure
3. Hook/callback: Expose an onTitleGenerate hook that lets users transform the title programmatically

Any of these would work. The core ask is just some mechanism to customize title generation based on user preferences.

Alternative Solutions

Currently, I manually edit conversation titles after they're generated to add emojis, which is time-consuming and interrupts my workflow.

Other tools like Notion and Linear allow custom title templates or prefixes, which could serve as inspiration for implementation.

Priority

Medium - Would be very helpful

Feature Category

Interactive mode (TUI)

Use Case Example

Example scenario:

1. I open the Claude Code sidebar and see a list of 20+ conversations
2. I'm looking for the conversation where I was debugging an authentication issue
3. With emoji prefixes, I could instantly spot "🔧 Fix auth bug" among conversations like "📊 Commission audit", "🎨 Update landing page", "🐛 Memory leak investigation"
4. This would save me 10-20 seconds every time I switch contexts (which happens dozens of times per day)

The visual differentiation makes it much faster to scan and find the right conversation compared to reading full text titles.

Additional Context

_No response_