* test: add regression test for stat directory scoping (#3019)
* fix: scope file-reference stat probes to the session directory (#3019)
The /api/fs/stat probe sent by the markdown renderer carried no
directory hint, so the server resolved the workspace from
settings.lastDirectory. When the browsed directory differs from the
session directory the stat returns 400 and the renderer treats it as
file-does-not-exist, silently disabling file-reference links.
Send effectiveDirectory as x-opencode-directory on the probe and
qualify the stat cache key by directory so a rejection under one
directory cannot leak into another. The probe logic moves from
MarkdownRendererImpl into fileReferenceStat with unit coverage.
Tom Rochette
a79ae57ae5