Session browser: Ctrl+K key binding conflict prevents CopyID from working

[aheritier]

Description

In the session browser dialog, Ctrl+K is bound to two different actions:

• Up navigation (sessionBrowserKeyMap.Up): key.WithKeys("up", "ctrl+k")
• Copy session ID (sessionBrowserKeyMap.CopyID): key.WithKeys("ctrl+k")

In the Update method, the Up case is checked before CopyID in the switch statement. Since both bindings match ctrl+k, pressing it always triggers up navigation — the CopyID handler is unreachable.

Steps to reproduce

1. Open the session browser (Ctrl+K → select Sessions, or the sessions command)
2. Select a session in the list
3. Press Ctrl+K — the selection moves up instead of copying the session ID to clipboard

Expected behavior

Pressing the designated "copy ID" shortcut should copy the selected session's ID to the clipboard.

Proposed fix

Reassign CopyID to Ctrl+Y (vim/emacs "yank" convention), keeping Ctrl+K for up navigation (consistent with Ctrl+J/Ctrl+K vim-style navigation used in the command palette).