A command line runs as its own command pane unless it is clicked at a shell's prompt

A middle click, an exec write or a tag word that no builtin knows was typed
into some terminal for the pane's directory, sharing whatever state that
shell was in and answering nothing, so a misspelling vanished into a shell.
Now only a line clicked at an interactive terminal's prompt is typed there.
From anywhere else it runs as a command pane: a terminal whose child is
$SHELL -c the line in the pane's directory, full emulation, which shows its
output and then exit N from the host's reaping of the child, and stays. A
finished command pane is the next command's for its directory, which runs
below what it showed after a '% line' line (acme appends to +Errors and never
clears it, util.c:213); a running one gets a second pane. Kill ends a command
pane's whole process group, the log records run and exit, exec reads back the
command pane's serial, and a line is at most 1 KB, read off the pane as the
host forks rather than carried in every spawn effect. ttyForDir's search for
a free shell is gone. The goldens of chordcut, cmdword and layout-open change
where a file's exec now opens a command pane, and ttytaken is rewritten to
exec from the terminal itself; docs/open-questions.md records the decision.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 17 insertions, 14 deletions

diff --git a/test/snapshots/cmdword.golden b/test/snapshots/cmdword.golden
index 99ad446b..0b6d91aa 100644
--- a/test/snapshots/cmdword.golden
+++ b/test/snapshots/cmdword.golden
@@ -4,21 +4,24 @@
 |   /tmp/pardes-snap/cmdword/cwd/cmds.txt Save Tty Collapse Del
 |     1 @`echo ZZ''E` @`echo ZZ''L` Look p.txt @`Look .`
 == snap atexec grid=120x31 cursor=7,3
-|17:    /tmp/pardes-snap/cmdword/cwd Tty Save Mode Filter Collapse Del
-|18:   echo ZZ''E
-|19:   ZZE
-== snap atlook grid=120x31 cursor=4,22
-|20:   echo ZZ''L
+|17:    /tmp/pardes-snap/cmdword/cwd (echo ZZ''E) exit 0 Kill Save Collapse Del
+|18:   ZZE
+|19:   exit 0
+== snap atlook grid=120x31 cursor=2,23
+|17:    /tmp/pardes-snap/cmdword/cwd (echo ZZ''L) exit 0 Kill Save Collapse Del
+|20:   % echo ZZ''L
 |21:   ZZL
+|22:   exit 0
 == snap lookword grid=120x31 cursor=7,11
 |10:    /tmp/pardes-snap/cmdword/cwd/p.txt Save Tty Collapse Del
 |11:      1 just text
-== snap nested grid=120x31 cursor=4,24
-|22:   ls
-|23:   cmds.txt  p.txt  zzmark.txt
-== snap execword grid=120x31 cursor=4,24
-|17:    /tmp/pardes-snap/cmdword/cwd Tty Save Mode Filter Collapse Del Exec
-== snap tagcmd grid=120x31 cursor=4,24
-|17:    /tmp/pardes-snap/cmdword/cwd Tty Save Mode Filter Collapse Del Exec @`echo ZZ''T`
-|24:   echo ZZ''T
-|25:   ZZT
+== snap nested grid=120x31 cursor=4,9
+|6:    /tmp/pardes-snap/cmdword/cwd Tty Save Mode Filter Collapse Del
+|7:   ls
+|8:   cmds.txt  p.txt  zzmark.txt
+== snap execword grid=120x31 cursor=4,9
+|6:    /tmp/pardes-snap/cmdword/cwd Tty Save Mode Filter Collapse Del Exec
+== snap tagcmd grid=120x31 cursor=4,7
+|6:    /tmp/pardes-snap/cmdword/cwd Tty Save Mode Filter Collapse Del Exec @`echo ZZ''T`
+|7:   echo ZZ''T
+|8:   ZZT