fix(cli): align command picker columns

[qkunio]

1. What does this PR do?

This PR fixes the slash command picker layout in the CLI.

Previously, each command row was rendered as adjacent text fragments. When the terminal was narrow, long command names and descriptions could wrap independently, causing the command column, description column, and row content to look misaligned.

Before：

After：

This change renders each row with a fixed command column and a flexible description column. The picker also uses the full available width so its border stays stable while the visible command window changes.

2. Why?

The command picker should remain easy to scan when command names are long or when the terminal width is constrained.

Without a stable command column, wrapped rows can split awkwardly, making selected skill commands look offset from the rest of the list.

3. How is this tested?

Ran:

bun run check

Result:

223 pass
0 fail

4. Checklist

• Command names use a stable column width.
• Descriptions wrap in a separate flexible column.
• Picker border uses the full available width to avoid width jumps.
• Code passes bun run check.