Left arrow opens agents panel despite keybinding unbound; scroll wheel permanently broken for affected conversation

Environment

• OS: Windows 10
• Terminal: Windows PowerShell
• keybindings.json: left unbound in both Tabs and Footer contexts

Steps to reproduce

1. Unbind left in Tabs and Footer contexts in keybindings.json
2. Open any chat conversation with empty input
3. Press left arrow (shown in UI hint as "< for agents")
4. Agents panel opens despite keybinding being unbound

What breaks

• Scroll wheel stops sending scroll events and instead sends up/down arrow key events — does not scroll
• Page Up / Page Down still scroll correctly
• Closing the agents panel does not fix it
• The conversation is now permanently hosted in the agents panel — every subsequent open re-enters the broken scroll mode
• No way to move the conversation back out of the agents panel
• Only workaround is to abandon the conversation and start a new one

Expected behavior

• Left arrow does nothing (binding is unbound)
• Scroll wheel scrolls

Two distinct bugs

1. Keybinding unbind is not respected — left arrow still triggers agents panel
2. Opening the agents panel via this path permanently associates the conversation with the agents panel and breaks scroll wheel for all future opens of that conversation