feat(term): replace vterm with ghostel as the terminal engine

I swapped the terminal engine from vterm to ghostel (libghostty-vt) everywhere. term-config replaces vterm-config (the F12 terminal, the C-; x menu, tmux history capture), and ai-term replaces ai-vterm (the F9 Claude-agent launcher). ghostel renders the agent TUI without vterm's flicker under heavy streaming, and one engine now covers every terminal workflow.

Two behavior changes fall out of the swap. F9 launches in a terminal frame now: ghostel renders in TTY frames, so the old GUI-only guard is gone. Terminal windows no longer dim when unfocused: ghostel resolves its palette into the native module per-terminal, so there's no per-window color hook to dim through the way vterm had.

auto-dim drops its vterm color-advice path, the dashboard Terminal button launches ghostel, and the vterm and vterm-toggle packages are removed. The tmux pane-history and copy-mode machinery carried over unchanged. It keys on the pty tty, which ghostel exposes.

1 files changed, 186 insertions, 0 deletions

diff --git a/tests/test-ai-term--single-window-toggle.el b/tests/test-ai-term--single-window-toggle.el
new file mode 100644
index 00000000..aa507f03
--- /dev/null
+++ b/tests/test-ai-term--single-window-toggle.el
@@ -0,0 +1,186 @@
+;;; test-ai-term--single-window-toggle.el --- F9 toggle round-trip when agent is the only window -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Regression coverage for the bug where toggling off a single-window
+;; agent (bury) then toggling on again redisplays the agent in a side
+;; split instead of restoring the full-frame layout.
+;;
+;; The fix introduces a `cj/--ai-term-last-was-bury' flag set at
+;; toggle-off when `one-window-p' was true.  At toggle-on the display
+;; action consumes the flag and, if the frame is still single-window,
+;; replaces the current window's buffer in place rather than calling
+;; `display-buffer-in-direction'.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(add-to-list 'load-path (expand-file-name "tests" user-emacs-directory))
+(require 'ai-term)
+(require 'testutil-ghostel-buffers)
+
+;;; Normal Cases
+
+(ert-deftest test-ai-term--single-window-toggle-normal-roundtrip-preserves-fullscreen ()
+  "Normal: agent in the only window, F9 (off), F9 (on) -> still single window with agent.
+
+Reproduces Craig's report.  Before the original fix the toggle-on path
+fell through to `display-buffer-in-direction', which split the lone
+window into two and left the agent in a side panel.  Before the
+follow-up fix the toggle-off path could no-op entirely when
+`bury-buffer' couldn't find a buffer to switch to, so the user saw
+\"F9 does nothing\".  The dispatcher now forces the swap to a non-
+agent buffer after bury so the toggle-off is observable in real and
+batch use both."
+  (cj/test--kill-agent-buffers)
+  (let ((agent-name "agent [single-window-roundtrip]")
+        (cj/--ai-term-last-was-bury nil)
+        (cj/--ai-term-last-direction nil)
+        (cj/--ai-term-last-size nil))
+    (unwind-protect
+        (save-window-excursion
+          (delete-other-windows)
+          (let ((agent-buf (get-buffer-create agent-name)))
+            (set-window-buffer (selected-window) agent-buf)
+            (should (one-window-p))
+            (let ((display-buffer-alist (cj/--ai-term-display-rule-list)))
+              ;; Toggle off -- the dispatcher's force-swap should put the
+              ;; window on a non-agent buffer.
+              (cj/test--call-as-gui #'cj/ai-term)
+              (should (one-window-p))
+              (should-not (cj/--ai-term-displayed-agent-window))
+              (should (eq cj/--ai-term-last-was-bury t))
+              ;; Toggle on -- should restore agent in the same lone window.
+              (cj/test--call-as-gui #'cj/ai-term)
+              (should (one-window-p))
+              (let ((win (cj/--ai-term-displayed-agent-window)))
+                (should (windowp win))
+                (should (eq (window-buffer win) agent-buf)))
+              ;; Flag consumed by the display-saved action.
+              (should-not cj/--ai-term-last-was-bury))))
+      (cj/test--kill-agent-buffers))))
+
+(ert-deftest test-ai-term--single-window-toggle-off-swaps-window-buffer ()
+  "Normal: toggle-off in single-window state forces the window onto a non-
+agent buffer when `bury-buffer' itself didn't swap.
+
+Catches the regression Craig reported after the original fix shipped:
+F9 in a lone-window agent did nothing visible.  The fix layer here
+ensures the displayed buffer changes -- so the next F9 sees an empty
+agent-window state and can route through the display-saved path."
+  (cj/test--kill-agent-buffers)
+  (let ((agent-name "agent [bury-swap-observable]")
+        (cj/--ai-term-last-was-bury nil))
+    (unwind-protect
+        (save-window-excursion
+          (delete-other-windows)
+          (let* ((agent-buf (get-buffer-create agent-name))
+                 (win (selected-window)))
+            (set-window-buffer win agent-buf)
+            (let ((display-buffer-alist (cj/--ai-term-display-rule-list)))
+              (cj/test--call-as-gui #'cj/ai-term))
+            (should (window-live-p win))
+            (should-not (cj/--ai-term-buffer-p (window-buffer win)))))
+      (cj/test--kill-agent-buffers))))
+
+(ert-deftest test-ai-term--single-window-toggle-normal-flag-set-on-bury ()
+  "Normal: single-window toggle-off sets the bury flag."
+  (cj/test--kill-agent-buffers)
+  (let ((agent-name "agent [bury-flag-set]")
+        (cj/--ai-term-last-was-bury nil))
+    (unwind-protect
+        (save-window-excursion
+          (delete-other-windows)
+          (let ((agent-buf (get-buffer-create agent-name)))
+            (set-window-buffer (selected-window) agent-buf)
+            (let ((display-buffer-alist (cj/--ai-term-display-rule-list)))
+              (cj/test--call-as-gui #'cj/ai-term)
+              (should (eq cj/--ai-term-last-was-bury t)))))
+      (cj/test--kill-agent-buffers))))
+
+(ert-deftest test-ai-term--single-window-toggle-normal-flag-cleared-on-multi-window-off ()
+  "Normal: multi-window toggle-off clears the bury flag.
+Mirrors the existing `delete-window' branch of the dispatcher --
+the flag should not carry over a prior bury into a delete-window
+toggle-off."
+  (cj/test--kill-agent-buffers)
+  (let ((agent-name "agent [bury-flag-clear]")
+        (left-name "*test-sw-left*")
+        (cj/--ai-term-last-was-bury t))    ; stale t from prior bury
+    (unwind-protect
+        (save-window-excursion
+          (delete-other-windows)
+          (let ((agent-buf (get-buffer-create agent-name))
+                (left-buf (get-buffer-create left-name)))
+            (set-window-buffer (selected-window) left-buf)
+            (let* ((agent-win (split-window (selected-window) nil 'right))
+                   (display-buffer-alist (cj/--ai-term-display-rule-list)))
+              (set-window-buffer agent-win agent-buf)
+              (select-window agent-win)
+              (cj/test--call-as-gui #'cj/ai-term)
+              (should-not cj/--ai-term-last-was-bury))))
+      (when (get-buffer left-name) (kill-buffer left-name))
+      (cj/test--kill-agent-buffers))))
+
+;;; Boundary Cases
+
+(ert-deftest test-ai-term--single-window-toggle-boundary-flag-respected-only-when-still-one-window ()
+  "Boundary: if the frame got split between toggle-off and toggle-on, the
+saved-direction split applies as usual.  The flag is a fast-path for the
+genuine single-window case, not an override for every redisplay."
+  (cj/test--kill-agent-buffers)
+  (let ((agent-name "agent [flag-fallback]")
+        (cj/--ai-term-last-was-bury t)        ; flag pretends prior bury
+        (cj/--ai-term-last-direction 'right)
+        (cj/--ai-term-last-size 40))
+    (unwind-protect
+        (save-window-excursion
+          (delete-other-windows)
+          (let* ((other-buf (get-buffer-create "*test-sw-other*"))
+                 (agent-buf (get-buffer-create agent-name)))
+            (set-window-buffer (selected-window) other-buf)
+            ;; Frame is split (two windows) -- single-window precondition
+            ;; for the flag no longer holds.
+            (split-window-right)
+            (should-not (one-window-p))
+            (let (received-buf
+                  (display-buffer-alist (cj/--ai-term-display-rule-list)))
+              (cl-letf (((symbol-function 'display-buffer-in-direction)
+                         (lambda (b _a)
+                           (setq received-buf b)
+                           (selected-window))))
+                (cj/--ai-term-display-saved agent-buf nil))
+              ;; The saved-direction split path ran (display-buffer-in-direction
+              ;; was called) rather than the in-place fast path.
+              (should (eq received-buf agent-buf))
+              ;; And the flag is cleared either way.
+              (should-not cj/--ai-term-last-was-bury))))
+      (when (get-buffer "*test-sw-other*") (kill-buffer "*test-sw-other*"))
+      (cj/test--kill-agent-buffers))))
+
+(ert-deftest test-ai-term--single-window-toggle-boundary-flag-not-set-when-bury-not-used ()
+  "Boundary: a fresh dispatcher run with the agent displayed multi-window leaves
+the flag nil (no spurious set)."
+  (cj/test--kill-agent-buffers)
+  (let ((agent-name "agent [bury-flag-untouched]")
+        (cj/--ai-term-last-was-bury nil))
+    (unwind-protect
+        (save-window-excursion
+          (delete-other-windows)
+          (let ((agent-buf (get-buffer-create agent-name))
+                (left-buf (get-buffer-create "*test-sw-untouched-left*")))
+            (set-window-buffer (selected-window) left-buf)
+            (let* ((agent-win (split-window (selected-window) nil 'right))
+                   (display-buffer-alist (cj/--ai-term-display-rule-list)))
+              (set-window-buffer agent-win agent-buf)
+              (select-window agent-win)
+              (cj/test--call-as-gui #'cj/ai-term)
+              (should-not cj/--ai-term-last-was-bury))))
+      (when (get-buffer "*test-sw-untouched-left*")
+        (kill-buffer "*test-sw-untouched-left*"))
+      (cj/test--kill-agent-buffers))))
+
+(provide 'test-ai-term--single-window-toggle)
+;;; test-ai-term--single-window-toggle.el ends here