[Bug] Opening threads creates Inbox drafts when “Keep addressed agents active” is enabled

**Describe the bug**

In Buzz Desktop v0.5.0, opening a thread causes that thread to appear as a draft in the Inbox view when **Keep addressed agents active** is enabled. No message needs to be typed or edited: clicking into a thread is enough. Repeating this across threads fills Inbox with drafts for every thread visited.

This appears to be a regression in the latest release.

**Steps to reproduce**

1. Install or update to Buzz Desktop v0.5.0.
2. Enable **Settings → Keep addressed agents active**.
3. Open the Inbox view.
4. Click into any thread without typing a message.
5. Return to Inbox.
6. Observe that the opened thread is now listed as a draft.
7. Repeat with other threads; each visited thread becomes a draft.

**Expected behavior**

Opening or viewing a thread should not create a draft. A thread should appear as a draft only after the user enters or changes unsent message content. Preselecting addressed agents should not count as draft content by itself.

**Version and platform**

- Buzz version: v0.5.0
- OS: unknown

**Logs / additional context**

The behavior is triggered by this setting:

> Keep addressed agents active
> Keep agents you address selected for future messages in the same channel or thread. Remove them from the composer at any time.


Duplicate check performed across open and closed `block/buzz` issues using the exact setting name and broader inbox/draft/thread and click/thread/draft searches; no matching report was found.

Reproduce the issue from the Inbox view with “Keep addressed agents active” enabled, then trace how opening a thread and changing composer selections affects draft state. Done means viewing a thread without entering or changing unsent message content does not list it as a draft, while actual unsent content still does.

Written by the indexing model from the issue text.