fix(audit): pass 1 — latent QT-hide bug, dead includes, header tidy

- QuickTerminal.cpp animateIn: clear the previous `finished -> hide()`
  handler that animateOut left attached to the cached
  QPropertyAnimation. Without this, an out-then-in cycle (autohide
  followed by re-toggle while the fade-out was still running) lets
  the leftover hide handler fire at the end of the in-fade and
  silently hide the just-revealed window. Latent in the original
  MainWindow code; fixed during the extraction.
- QuickTerminal.cpp kAnimProperty: rename `_ghastty_qt_anim` →
  `ghastty.quickterm.anim`. Qt reserves the underscore-prefix
  property namespace; the dotted form is application-scoped and
  unambiguous.
- QuickTerminal.cpp setupLayerShell: comment the `screen` reassignment
  after `ls->setScreen(...)` so a future reader doesn't think the
  anchor is being re-pointed. The reassignment is for sizing only.
- MainWindow.h: drop stale `<QRect>` and `<QStringList>` includes
  (UndoEntry-era leftovers; consumers that need them include them
  directly), and drop the orphaned three-line comment that survived
  the m_quickTerminalAnim member removal.
- UndoStack.{h,cpp} pushTab: drop the dead `quickTerminal` parameter.
  Every caller in MainWindow.cpp already gates on `!m_quickTerminal`,
  so the function-local re-check was vacuous; the comment now
  documents the caller-side contract.
- XkbState.cpp: include `<xkbcommon/xkbcommon.h>` directly per IWYU
  (was reaching it transitively through XkbState.h); cache the
  XkbTracker singleton in `consumedMods` instead of calling
  `XkbTracker::instance()` twice in succession.
- GhosttySurface.cpp: drop the now-dead `XkbTracker.h` include — the
  TU's only XkbTracker reference moved into XkbState.cpp during
  Phase 7. The remaining mention of "XkbTracker" in this file is a
  doc comment, not code.

Co-Authored-By: claude-flow <ruv@ruv.net>

qt/src/GhosttySurface.cpp

@@ -8,7 +8,6 @@
 #include "SearchBar.h"
 #include "TabWidget.h"
 #include "Util.h"
-#include "XkbTracker.h"
 
 #include <algorithm>
 #include <cmath>

qt/src/MainWindow.cpp

@@ -440,7 +440,7 @@ void MainWindow::removeSurface(GhosttySurface *surface) {
   // double-stack. Also skip the quick terminal (which doesn't push
   // to either stack by design).
   if (index >= 0 && m_tabs->count() > 1 && !m_quickTerminal)
-    undo::pushTab(m_tabs->tabText(index), m_quickTerminal);
+    undo::pushTab(m_tabs->tabText(index));
   if (index >= 0) m_tabs->removeTab(index);
   if (parent) parent->deleteLater();  // page; destroys the surface too
   // The surface close was already confirmed; don't re-prompt on the
@@ -458,7 +458,7 @@ void MainWindow::closeTab(int index) {
   // undo::pushTab is no-op for the last tab in a window — that close
   // ends up triggering undo::pushWindow via closeEvent instead.
   if (m_tabs->count() > 1 && !m_quickTerminal)
-    undo::pushTab(m_tabs->tabText(index), m_quickTerminal);
+    undo::pushTab(m_tabs->tabText(index));
   const auto inTab = page->findChildren<GhosttySurface *>();
   for (GhosttySurface *s : inTab) m_surfaces.removeOne(s);
   // If the zoomed surface was in this tab, clear the stash so a later

qt/src/MainWindow.h

@@ -1,9 +1,7 @@
 #pragma once
 
 #include <QList>
-#include <QRect>
 #include <QSize>
-#include <QStringList>
 #include <QWidget>
 
 #include "ghostty.h"
@@ -227,9 +225,6 @@ private:
   ghostty_surface_t m_firstTabParent = nullptr;  // inherited by the 1st tab
   bool m_skipCloseConfirm = false;     // close already confirmed elsewhere
   bool m_quickTerminal = false;        // this is the dropdown quick terminal
-  // Per-window opacity animation for the quick terminal (fade in/out
-  // using quick-terminal-animation-duration). Owned by quickterm/'s
-  // dynamic-property cache on this widget; cleared on widget delete.
   QSize m_defaultWindowSize;           // for RESET_WINDOW_SIZE; from INITIAL_SIZE
   // Last cell size reported by libghostty for this window's surfaces
   // (CELL_SIZE action). Stored so future grid-snap resizing can use

qt/src/input/XkbState.cpp

@@ -1,5 +1,7 @@
 #include "XkbState.h"
 
+#include <xkbcommon/xkbcommon.h>
+
 #include "../XkbTracker.h"
 
 XkbState &XkbState::instance() {
@@ -70,8 +72,8 @@ ghostty_input_mods_e XkbState::consumedMods(uint32_t keycode,
     depressed |= (1u << m_idxSuper);
   // Use the live group from the tracker so a layout switch (e.g.
   // us↔ru) takes effect immediately.
-  const uint32_t group =
-      XkbTracker::instance() ? XkbTracker::instance()->activeGroup() : 0;
+  XkbTracker *t = XkbTracker::instance();
+  const uint32_t group = t ? t->activeGroup() : 0;
   xkb_state_update_mask(m_query, depressed, 0, 0, 0, 0, group);
   const xkb_mod_mask_t consumed = xkb_state_key_get_consumed_mods2(
       m_query, keycode, XKB_CONSUMED_MODE_XKB);

qt/src/quickterm/QuickTerminal.cpp

@@ -25,8 +25,10 @@ namespace {
 
 // Anim and toggle live on the QObject child tree of `window`, so
 // they die with it. We keep the QPropertyAnimation as a dynamic
-// property so callers don't need to thread it through.
-constexpr const char *kAnimProperty = "_ghastty_qt_anim";
+// property so callers don't need to thread it through. The "_q_"
+// underscore-prefix space is reserved by Qt; any other prefix is
+// fine and the dotted form keeps it visibly application-scoped.
+constexpr const char *kAnimProperty = "ghastty.quickterm.anim";
 
 // Read quick-terminal-animation-duration (seconds) and convert to ms.
 // Clamps to a sane range so a misconfigured 0/negative value doesn't
@@ -98,6 +100,9 @@ void setupLayerShell(QWidget *window) {
     screen = QGuiApplication::primaryScreen();
   }
   ls->setScreen(screen);
+  // For sizing only — LayerShellQt already has the anchor screen above
+  // (or fell back to the QWindow's screen via setScreen(nullptr)). We
+  // need a non-null QScreen below to read its pixel dimensions.
   if (!screen) screen = handle->screen();
 
   // quick-terminal-space-behavior (`remain` / `move`) is intentionally
@@ -171,6 +176,12 @@ void animateIn(QWidget *window) {
   // animations.
   QPropertyAnimation *anim = animFor(window);
   anim->stop();
+  // animateOut leaves a `finished -> hide()` handler attached to the
+  // shared animation object. If a fade-out was interrupted by this
+  // fade-in (rapid out/in cycle), the leftover handler would fire at
+  // the end of the in-fade and silently hide the just-revealed
+  // window — clear it before starting.
+  QObject::disconnect(anim, &QPropertyAnimation::finished, window, nullptr);
   anim->setDuration(ms);
   anim->setStartValue(0.0);
   anim->setEndValue(1.0);

qt/src/undo/UndoStack.cpp

@@ -74,9 +74,8 @@ void pushUndo(Entry e) {
 
 }  // namespace
 
-void pushTab(const QString &tabText, bool quickTerminal) {
+void pushTab(const QString &tabText) {
   if (g_redoInProgress) return;
-  if (quickTerminal) return;
   Entry e;
   e.kind = Entry::Kind::Tab;
   e.pageTitles << tabText;

qt/src/undo/UndoStack.h

@@ -30,11 +30,10 @@ struct Entry {
   QRect geometry;
 };
 
-// Snapshot the tab at `index` — single title — onto the undo stack.
-// `tabText` is the tab's last-known display text; `quickTerminal` is
-// the window's quick-terminal flag (quick-terminal tabs are excluded
-// from the stack, mirroring the prior MainWindow behavior).
-void pushTab(const QString &tabText, bool quickTerminal);
+// Snapshot a closed tab — its last-known display text — onto the
+// undo stack. Callers MUST exclude quick-terminal and last-tab
+// closes (the latter routes through pushWindow via closeEvent).
+void pushTab(const QString &tabText);
 
 // Snapshot every tab's title plus the window's geometry as a single
 // Window entry. Excluded for the quick terminal and for empty