VS Code extension: history dropdown empty despite many local session JSONLs on disk

Environment

• Extension: anthropic.claude-code 2.1.145 (win32-x64)
• VS Code: latest stable on Windows 11
• Workspace: l:\ (SMB-mounted drive from a TrueNAS share, mapped to drive letter L:)
• Session JSONLs are written normally to %USERPROFILE%\.claude\projects\l--\*.jsonl — so the storage itself lives on local C:, only the workspace is on SMB.

Expected

The clock-icon "Local" tab in the chat panel should list past sessions I've had in this workspace. I have 11+ JSONL files in ~/.claude/projects/l--/, including sessions from this week.

Actual

The Local tab is empty except for the currently active session. New sessions started in the extension don't survive a Reload Window — after reload, the history list is empty again. Sessions are clearly being saved (JSONL files appear and grow on disk during the session), but the dropdown never surfaces them.

Investigation

• ~/.claude/projects/l--/*.jsonl contains 11 valid sessions, most recent today. Their content is intact.
• Reading the extension log at %APPDATA%\Code\logs\<timestamp>\window1\exthost\Anthropic.claude-code\Claude VSCode.log, I can see the webview sends {type: "request", request: {type: "list_sessions_request"}} when the dropdown opens, and also sends get_session_request for specific session IDs that do exist on disk (e.g., 78bebbdd-…). So the extension knows about at least some sessions individually, but they don't appear in the dropdown UI.
• I generated a sessions-index.json in ~/.claude/projects/l--/ modeled on ones present in two of my older project folders (Z--, C--Users-bkpun-dev-echolog). No effect.
• ~/.claude.json's projects dict has no entry for L:/ or L:\\. I don't know if that's the cause — my Z:/ project IS listed there and (according to a quick check) has the same empty-dropdown symptom.

Workaround

claude --resume from the integrated terminal works fine and finds all sessions. The bug is specifically in the extension's history surface — disk persistence and the CLI resume path are both healthy.

Repro hints

• May relate to projects on uncommon drive letters (L:, Z:) or to workspaces with no entry in ~/.claude.json's projects dict.
• Sessions that end via Reload Window (not a graceful /exit) never get a type:"summary" line written at the top of their JSONL. Possibly the dropdown filter requires that record?
• All my JSONLs in this project start with {"type":"queue-operation","operation":"enqueue",…} as their first line. One of them has {"type":"ai-title",…} as its first line and still doesn't show.