[BUG] Desktop app (macOS): persisted local sessions load in main process but never render in sidebar / Cmd+K after relaunch

What happens

On the Claude desktop app (macOS), the conversation sidebar is empty after every relaunch. Only sessions created in the current run appear; all previously persisted sessions are missing from both the sidebar and Cmd+K — even though the app's own main process loads them correctly on startup.

This is not data loss and not the moved-folder path issue (cf. #33636). The session files are present and the stored paths are correct; the data reaches the main process but is never rendered by the UI.

Evidence

~/Library/Logs/Claude/main.log on each launch:

[info] Loaded 31 persisted sessions from .../claude-code-sessions/<account>/<org>
[info] Loaded 15 persisted sessions from .../local-agent-mode-sessions/<account>/<org>

• 32 local_*.json files exist under claude-code-sessions, 15 under local-agent-mode-sessions.
• All cwd values in the session JSONs point at current, valid paths — no stale/orphaned project directories under ~/.claude/projects/.
• No Filtering out deleted folder warnings in recent logs.
• Sessions remain fully reachable via claude --resume <cliSessionId> and via the MCP session-list tools (same main process) — confirming the data is intact and only the renderer fails to show it.

Key detail: freshly created, post-relaunch sessions with clean paths also vanish from the sidebar after the next restart, while the log still reports them loaded. This points squarely at the renderer/sidebar, not at storage or path resolution.

Regression window

Sidebar worked on app 1.20186.1. Broke after 1.20186.9 (activated 2026-07-14). Still broken on 1.21459.0 (2026-07-15).

Environment

• Claude desktop app: 1.21459.0
• macOS: 26.3.1

Impact

All conversation history is inaccessible through the normal UI; only the CLI --resume workaround functions.