fix(terminal): report the pane directory in the workspace's own spelling

tmux reads a pane's directory from the process cwd, which is always the
resolved path, while workingDir keeps the spelling the case was created
with. For a workspace reached through a symlink every reading looked
like it was outside the workspace, so the browser sent each relative
link through the attachment route instead of the workspace routes.

Each session now resolves workingDir once in the background, bounded by
probePathKind() and a timed realpath(), and setCwd() writes a reading at
or under the resolved path back in workingDir's spelling. Until that
settles only a reading lexically inside workingDir is taken. An unknown
probe or a failed realpath leaves readings untranslated and retries
after WORKSPACE_REALPATH_RETRY_MS.

Also corrects two comments: cwd is written to state.json but never read
back, and a blank pane path is usually a pane whose program exited.

src/config/path-probe.ts

@@ -46,3 +46,10 @@ export const MAX_STALLED_PATH_PROBES = Math.min(
   PATH_PROBE_STALL_CEILING,
   envInt('CODEMAN_PATH_PROBE_MAX_STALLED', Math.max(1, PATH_PROBE_STALL_CEILING - 1), 1, 64)
 );
+
+/**
+ * How long a session waits before trying again to resolve its workspace's symlinks
+ * after the folder did not answer, so a mount that recovers is picked up (the pane
+ * directory reading stays in the resolved spelling meanwhile).
+ */
+export const WORKSPACE_REALPATH_RETRY_MS = 60_000;