Agents: Persist user's choice of closing the Changes panel in new sessions

[bamurtaugh]

• Open Agents
• The Changes panel with the Files tab selected opens by default (which is an expected change from last week ✅)
• I click on Show Changes to now minimize the Changes panel
• I reload the Agents app
• ❓ The Changes panel reopens after reload. I would've expected my choice to be preserved (for the entire Agents app, or at least while I still have the same workspace selected in the new session dropdown)

[lostintangent]

This was resolved last week 👍🏼