Feature hasn't been suggested before.

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Describe the enhancement you want to request

Problem

Currently, opencode has tabs (which are great), but there's no persistent left rail/sidebar for quick access to projects and previous chats. Users have to navigate away or lose easy access to their conversation history across sessions.

Proposed solution

Add a collapsible left rail that includes:

1. Projects – list of active/recent projects with ability to switch between them
2. Chat history – list of previous conversations, searchable and filterable by name or date
3. Ability to organize, rename, or archive chats

This would coexist alongside existing tab support, not replace it — tabs for working on multiple topics within a chat/project, left rail for switching between different projects/chats.

Why this matters

• Reduces context switching — navigate between conversations/projects without losing your place
• Keeps the UI intuitive — familiar pattern (similar to VS Code's sidebar activity bar)
• Complements tabs beautifully: tabs = "what I'm working on right now", left rail = "where am I doing it"

UX reference

Similar patterns used successfully by:

• VS Code (left panel for projects + chat history alongside tab system)
• Linear (project/navigator sidebar + top tabs)