desktop: crash when switching between two projects/communities (Linux AppImage)

## Summary
Buzz Desktop hard-crashes when switching between two projects/communities in the left sidebar. Reproduces **every time**.

## Environment
| | |
|--|--|
| **App** | Buzz Desktop |
| **Version** | 0.5.3 |
| **Install** | **AppImage** (`Buzz_0.5.3_amd64.AppImage` / from desktop-v0.5.3 release) |
| **OS** | Linux, Ubuntu/Kubuntu 24.04 family, x86_64 |
| **Hosted vs self-host** | _(hosted buzz.xyz unless noted otherwise)_ |

## Steps to reproduce
1. Launch Buzz Desktop (AppImage) with **two** projects/communities in the left project rail (e.g. avatars **“H”** and **“BL”**).
2. Stay in project A (channels visible: `#general`, Welcome, etc.).
3. Click the other project in the left rail to switch to project B.
4. App crashes.

## Expected
Workspace switches cleanly to the other project; channels/inbox load.

## Actual
Process **exits/crashes** on every project switch. Must restart the AppImage.

## Frequency
**Always** (100%).

## Screenshot
Attached: left sidebar with two project switchers; crash path = clicking the other project.

## Workaround
None (avoid switching projects, or restart after each crash).

## Notes
Happy to retest on newer desktop builds or with debug logging if documented.