Autostart setting is re-enabled on every Claude Desktop update, even when previously disabled

**Description:**
Every time Claude Desktop auto-updates, the "Start Claude at login" / autostart setting is silently switched back to enabled, even though I had explicitly turned it off before the update. This has happened consistently across multiple update cycles, not just once.

**Steps to reproduce:**
1. Open Claude Desktop settings and disable "Start Claude at login" (autostart = false).
2. Confirm the setting shows as disabled and restart the machine to verify Claude does not launch automatically.
3. Let Claude Desktop auto-update to a new version (or manually trigger an update).
4. Check the autostart setting again after the update completes.

**Expected behavior:**
The autostart setting should persist across updates and remain disabled, since it's a user preference, not a default that should be reset by the installer.

**Actual behavior:**
After the update, autostart is enabled again (true), and Claude launches automatically at the next login without my consent.

**Environment:**
- Claude Desktop version: v2.110.0
- Claude Code version: v2.1.267
- OS: Windows 11 Business 25H2, OS Build 26200.9168

**Possible related cause:**
This may be related to how the installer (MSIX) registers autostart/login-item entries at the package level during installation/update, rather than persisting the user's saved preference. See related reports:
- #57221 (CoworkVMService AutoStart baked into MSIX package, causing update/launch issues)
- #59802 (Autostart registry entry causing Windows Settings > Startup to crash)

**Impact:**
Minor privacy/control annoyance — the app overrides an explicit user choice without notification, and users have to manually re-disable it after every single update.

**Suggested fix:**
Persist the user's autostart preference across updates (e.g., store it outside the reinstalled package, or have the updater read and reapply the previous value instead of falling back to a package default)

Start by tracing the Windows MSIX installation and update path that registers Claude Desktop for autostart, then compare it with the persisted user preference described in the issue. Review related reports #57221 and #59802 for context. Done means disabling autostart remains effective after an update and the app does not launch at the next login.

Written by the indexing model from the issue text.