Read a session's transcript as the file it is

The conversation on screen is a drawing of the record, and when the two
disagree -- or when something in the record is what has gone wrong -- there
was no way to see the record itself from the phone.

View raw in the session settings dialog opens the file explorer on the
transcript, which is its third caller and needed no new screen: the file
name and path in the header, a back button, and the lines as code. The
session says where the file is, because only the backend knows, and it
names this backend's machine rather than the session's -- for a remote
session those are two different filesystems. Back from the file lands in
the session's own directory, where the log and the process record are.

The paragraph under Reload goes, and both buttons move to a line of their
own: two buttons and a measurement do not fit a phone's width.

EXPLORER.md

@@ -37,6 +37,18 @@ Rejected: routes under `/sessions/{id}/`. The session would be a detour to
 find the machine, and "browse this machine" from anywhere else would need a
 session to exist first.
 
+The third caller arrived 2026-09-21 and cost no code here, which is the
+property this decision was made for: **View raw** in the session settings
+dialog opens the explorer on the session's own transcript file
+(`fileTarget`), so the record can be read as it is on disk rather than only
+as the conversation drawn from it. The session says where the file is
+(`transcriptFile` on `GET /sessions/{id}`) because only the backend knows --
+and it names **this backend's** machine rather than the session's, which for
+a remote session are two different filesystems. Back from the file lands in
+the session's own directory, where the log and the process record are.
+A transcript past `FILE_LIMIT` is refused the same way any other large file
+is, which is the known limit of this as a debugging tool.
+
 ### 2. One shell script per operation, over `Transport`, on both transports
 
 Each operation is a small POSIX script handed to `sh -c script sh "$path" …`