The session directory now contains two peers: content/ (HTML served to
the browser) and state/ (events, server-info, pid, log). Previously
all files shared a single directory, making server state and user
interaction data accessible over the /files/ HTTP route.
Also fixes stale test assertion ("Waiting for Claude" → "Waiting for
the agent").
Reported-By: 吉田仁
Metadata files (.server-info, .events, .server.pid, .server.log,
.server-stopped) were stored in the same directory served over HTTP,
making them accessible via the /files/ route. They now live in a .meta/
subdirectory that is not web-accessible.
Also fixes a stale test assertion ("Waiting for Claude" → "Waiting for
the agent").
Reported-By: 吉田仁
