All sessions/chats disappeared from sidebar after re-login (lost ~1 month of work)

After being forced to log in again, the Claude Code desktop app (Code tab) no longer shows any of my previous projects or chats in the sidebar — including work from roughly the past month. I only have one Claude account, so this isn't an org/workspace mismatch.

**Environment:**
- macOS 26.6.2 (build 25G83)
- Claude Code desktop app (Code tab)

**Steps to reproduce:**
1. Was using Claude Code normally with multiple sessions/projects over the past month.
2. Got logged out and had to log in again.
3. After re-login, the sidebar shows no previous sessions — not even archived ones.

**Expected:** Previous sessions/chats should still be listed after re-authenticating with the same account.

**Actual:** Sidebar is empty; no sessions found via the app's session list either.

**Impact:** Appears to have lost visibility into ~1 month of prior work/chat history.

No files or tests are named. Start in the Claude Code desktop app's Code tab by reproducing logout and re-login, then trace how the sidebar and session list load prior projects. Done means sessions and chats from before re-authentication remain visible for the same account.

Written by the indexing model from the issue text.