fix(edit-history): remote lookup finds tmux, a timeout reaches ssh, docs follow

Applies the review of #766.

The live lookup ran tmux on the bare PATH of the ssh command. On a host
where tmux sits in ~/.local/bin or /opt/homebrew/bin it found no pane, the
2>/dev/null hid that, and the panel stayed on the launch conversation after
a /clear. It now goes through withRemoteTmuxPath(), inside the sh script and
scoped to the $(...), so the other tools keep the PATH they had. The fake
tmux of the test block moved to $HOME/.local/bin for the same reason: that
directory is first on the new PATH, so a real tmux is never asked.

The two ssh commands get exec. Node signals the local sh -c, and dash stays
the parent of a plain command, so ssh survived the timeout. A test with a
fake ssh shows the process dies now and survives without exec.

The comment at the meta budget claimed a meta past it comes with a later
read. A meta comes only with a subagent's first read, so it is never sent.

Docs: the store is named as the exception to "never copied to local disk",
remoteProbePaths and the remote transcript lookup are described, and the
line saying a remote session loads no store is gone.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/wiki/Working-With-Files.md

@@ -147,8 +147,8 @@ session uses: one `realpath` plus `stat` probe for the file and the workspace ro
 streamed `cat` (or a slice of it, so video seeking works). Symlinks are resolved on the host
 that can resolve them, the size cap applies to the remote size before a byte is requested,
 and an unreachable host answers 502 rather than pretending the file is missing. Nothing is
-ever copied onto the Codeman host, and a same-named local file is never served under a
-remote name.
+ever copied onto the Codeman host, apart from the diffs the [edit history](#edit-history)
+stores, and a same-named local file is never served under a remote name.
 
 Not available over ssh, and said so with a 400 instead of a misleading 404: editing in
 place, Office previews and generated thumbnails (both need the bytes on the server's disk),