CLI-created sessions invisible in Desktop app (reverse direction broken)

Bug Description

CLI-created sessions are invisible in the Claude Desktop app, but Desktop-created sessions can be viewed in CLI via resume. This is a one-way sync issue.

How to Reproduce

1. Open Claude Code CLI directly (not launched from Desktop app)
2. Have a conversation — session is saved to ~/.claude/projects/{project}/{sessionId}.jsonl
3. Open Claude Desktop app
4. The session does not appear in the session list

Reverse direction works fine:

1. Create a session in the Desktop app
2. Use claude --resume in CLI — the session is found and accessible

Root Cause

The two entry points use different session registration mechanisms:

| | CLI | Desktop |
|---|---|---|
| Conversation data | ~/.claude/projects/{project}/{id}.jsonl | ~/.claude/projects/{project}/{id}.jsonl |
| Session metadata | ~/.claude/sessions/{pid}.json | AppData/Local/Claude-3p/claude-code-sessions/{group}/{sub}/local_{id}.json |

• Desktop → CLI works because CLI resume reads JSONL files directly from ~/.claude/projects/
• CLI → Desktop fails because Desktop discovers sessions by scanning AppData/Local/Claude-3p/claude-code-sessions/, and CLI never creates metadata files there

Expected Behavior

CLI-created sessions should appear in the Desktop app's session list, either by:

• CLI writing metadata to the AppData location when a Desktop group exists
• Desktop also scanning ~/.claude/projects/ for JSONL files without AppData metadata
• A sync mechanism that reconciles the two registries

Environment

• Claude Code version: 2.1.149
• OS: Windows 11 Pro
• Both CLI and Desktop app (claude-desktop-3p entrypoint)