feat: party clean rescues an orphaned transcript before deleting

A server crash mid-logged-party is the one case close's rescue can
never have run, and host's EEXIST message funnels the host straight
into clean. Deleting the night's log there is exactly the accident
class the close-time rescue exists for, so clean applies the same
rescue: no quiescence poll needed, the liveness gate just proved the
writers are gone.

party

@@ -1005,6 +1005,21 @@ EOF
             echo "party clean: skipping $d (server is live; use party close)." >&2
             continue
         fi
+
+        # A crash-orphaned transcript is the same "lost the night's log"
+        # accident cmd_close's rescue exists for; the server here is
+        # already confirmed dead by the liveness check above, so unlike
+        # close there's no pipe-pane `cat` still draining and no
+        # quiescence poll is needed before moving it.
+        if [ -s "$d/log" ]; then
+            _cn_name=${d##*"party-$USER:"}
+            _cn_name=${_cn_name%.d}
+            _cn_dest="$HOME/party-$_cn_name-$(date -u '+%Y%m%d-%H%M%S').log"
+            if mv "$d/log" "$_cn_dest" 2>/dev/null; then
+                echo "party clean: transcript saved to $_cn_dest"
+            fi
+        fi
+
         rm -rf "$d"
         echo "removed $d"
         removed=$((removed+1))