[Feature Request] Display session colors in /resume picker

Bug Description
Show /color in the /resume session picker

When sessions are set with /color, that color isn't reflected in the /resume
picker — every session row looks the same. It would be great if the picker
rendered each session row using its assigned color (or showed a small color
swatch next to the name).

Why it helps:

• Makes it easy to visually distinguish sessions at a glance when resuming
• Reinforces the mental model users already build by assigning colors to

specific projects/tasks

• Complements --name, which helps textually but not visually

Ideal behavior: session rows in /resume are tinted (or prefixed with a swatch)
matching the /color that was active when the session was last used.

Environment Info

• Platform: linux
• Terminal: ghostty
• Version: 2.1.118
• Feedback ID: d5629394-e07c-4896-8a8d-e36f11af8932