auto_index/auto_watch doesn't follow OpenCode's /cd directory change #2821

Environment

• codebase-memory-mcp 0.12.1, OpenCode (MCP profile: --tool-profile=analysis)
• auto_index=true, auto_watch=true

Repro

1. Start OpenCode from $HOME (or any non-target dir).
2. Run /cd (keybind session.cd).
3. Query index_status for the new project.

Expected

The new directory is auto-indexed and watched, as if OpenCode started there.

Actual

Nothing is indexed or watched. index_status reports
"watched": false, "reason": "not_session_project".

Root cause

1. cbm roots auto_index/auto_watch at the MCP session's startup directory, not
   the client's cwd (fix(watcher): show watch state in index_status, correct auto-sync docs (#2167) #2348: "only watches the project an open MCP session is
   rooted in"). /cd changes the session dir without restarting the MCP process,
   so cbm never re-roots.
2. The plugin cbm-augment.ts reads ctx.directory once at server() init
   (~line 42) and only hooks tool.execute.after + experimental.session.compacting
   — nothing observes a directory change. OpenCode's plugin API also exposes
   directory only as a static load-time value and has no directory-change event.

Suggested direction

Detect session-directory changes (via the plugin or the MCP server) and re-root
auto_index/auto_watch + index_repository for the new root.

Related

• auto_watch misses successful index_repository targets from another session root #2733 / fix: watch explicit MCP index targets #2737 (same not_session_project mechanism, explicit-index trigger)
• fix(watcher): show watch state in index_status, correct auto-sync docs (#2167) #2348 (documents session-rooted watcher behavior)