Add color labels and stronger color indicators for chats and projects

What feature would you like to see?

Please add color labels for Codex chats and projects, not only project/group icons.

When many chats are active in parallel, icons are too weak as a visual signal. I have to read chat titles line by line to find the right context. Stronger color coding would make it possible to recognize projects, task types, and urgency almost instantly through peripheral vision.

Suggested behavior:

• Allow assigning a color to a project.
• Allow assigning a separate color or color label to an individual chat.
• Let chats inherit the project color by default.
• Allow overriding the inherited color for a specific chat.
• Show a visible 4–6 px vertical color bar along the full height of the chat row.
• Optionally add a very subtle tinted background to the entire row.
• Support filtering chats by color.
• Optionally support multiple custom color tags.

Example personal scheme:

• Red — critical issue
• Orange — requires my decision
• Yellow — research
• Green — completed or verified
• Blue — architecture
• Purple — personal project

The color indicator should be directly visible in the chat list without opening the project or hovering over the row.

Why is this useful?

The main goal is to navigate dozens of parallel Codex sessions without reading every title. A small colored dot or recolored icon would likely still be too subtle; a vertical color bar plus a light row tint would provide much faster visual orientation.