[BUG] Zed ACP registry mode shows stale Recent sessions (unscoped /session) #16137

Summary

When OpenCode is used from Zed via the ACP registry entry, the Recent conversations list appears frozen/stale and does not show newly created sessions.
Switching Zed to custom command mode immediately shows current sessions.

Environment

• Zed (ACP external agent via registry)
• OpenCode 1.2.17
• Registry command entry: opencode acp (from registry.json)
• Linux (Zorin)

Repro

1. In Zed, configure OpenCode via ACP registry (not custom command).
2. Create several new conversations in different project directories.
3. Open Recent conversations in Zed ACP UI.
4. Observe list stays on older items (looks like not saving/updating).
5. Switch to custom command mode (opencode custom type), then re-open Recent.
6. Observe current conversations appear.

What I verified locally

• Sessions are persisted in ~/.local/share/opencode/opencode.db (new rows are present).
• In registry mode, the ACP process runs from a registry path and has no explicit workspace cwd.
• GET /session (no query) returns the same stale list seen in Zed.
• GET /session?directory=<active-project-dir> returns expected current sessions.

This looks like a scope/default-directory mismatch for session listing in registry mode, not a DB write failure.

Suspected fix

Either:

1. Have Zed pass active worktree directory when requesting session history, or
2. Have OpenCode ACP default /session behavior be workspace-aware / less dependent on process cwd in registry launches.

Extra signal

In one registry-launched process log I also saw:

• setRawMode failed with errno: 5
  which may contribute to ACP process instability in some runs.