Chord: suppress middle-click primary paste on both press and release

The X11 primary-selection paste was leaking through on the middle-button
release because only the press was consumed. Now the middle button is
consumed inside the editor on BOTH press and release (tracked via
m_swallowMiddleRelease), fully suppressing primary paste there. The chord
Cut uses edit_cut, which writes to the standard KDE clipboard (Klipper), so
paste is the normal Ctrl+V / palette paste. All 5 ctest suites green.

docs/PLAN.md

@@ -131,10 +131,13 @@ Therefore the palette is replaced, not extended, and the replacement is built on
 ### Mouse chording (Acme-style) — DONE (first increment)
 - Left+middle chord = **Cut**: with the left button held while selecting
   (button 1 anchor), a tap of the middle button (button 2) cuts the current
-  selection. Driven by the same application event filter — it tracks the left
-  button held inside the view and, on a middle press while held, triggers
-  `edit_cut` and consumes the event. Middle-click alone (no left held) still
-  does the usual primary-selection paste.
+  selection via `edit_cut`, which uses the **standard KDE clipboard**
+  (Klipper-backed), not the X11 primary selection.
+- **Middle-click primary paste is suppressed** inside the editor. Kate pastes
+  the primary selection on the middle event; the filter consumes the middle
+  button on **both press and release** (swallowing only the press let the paste
+  leak through on release). So middle-click no longer pastes in the editor —
+  paste is the normal `Ctrl+V` / palette paste from the KDE clipboard.
 - Right-button chords are intentionally **not** ported — the right button is the
   radial gesture. (Revisit later.)
 - The radial gesture is suppressed while the left button is held, so an RMB tap

src/plugin/ollieplugin.cpp

@@ -347,25 +347,38 @@ bool OllieView::eventFilter(QObject *obj, QEvent *event)
         }
     }
 
-    // Acme-style left+middle chord = Cut. Button 1 (left) held while selecting
-    // is the anchor; a tap of button 2 (middle) cuts the current selection.
+    // Acme-style left+middle chord = Cut, and suppression of X11 primary-
+    // selection paste. Middle-button events inside the view are consumed on
+    // BOTH press and release (Kate pastes the primary selection on the middle
+    // event; swallowing only the press lets the paste leak through on release).
+    // When the left button is held, the middle tap cuts the current selection
+    // via edit_cut, which uses the standard KDE clipboard (Klipper-backed).
     // Right-button chords are intentionally not ported (RMB is the radial).
-    // Middle-click alone (no left held) still does the usual primary paste.
     if (event->type() == QEvent::MouseButtonRelease) {
-        if (static_cast<QMouseEvent *>(event)->button() == Qt::LeftButton) {
+        auto *mev = static_cast<QMouseEvent *>(event);
+        if (mev->button() == Qt::LeftButton) {
             m_leftDownInView = false;
         }
+        if (mev->button() == Qt::MiddleButton && m_swallowMiddleRelease) {
+            m_swallowMiddleRelease = false;
+            return true; // suppress the primary paste that fires on release
+        }
     } else if (event->type() == QEvent::MouseButtonPress) {
         auto *mev = static_cast<QMouseEvent *>(event);
         KTextEditor::View *v = m_mainWindow->activeView();
         auto *w = qobject_cast<QWidget *>(obj);
         const bool inView = v && w && v->isAncestorOf(w);
 
-        if (mev->button() == Qt::MiddleButton && m_leftDownInView && inView) {
-            if (QAction *cut = findActionByName(QStringLiteral("edit_cut"))) {
-                cut->trigger();
+        if (mev->button() == Qt::MiddleButton && inView) {
+            if (m_leftDownInView) {
+                if (QAction *cut = findActionByName(QStringLiteral("edit_cut"))) {
+                    cut->trigger();
+                }
             }
-            return true; // consume: this is the chord, not a primary paste
+            // Consume press (and its release) to suppress middle-click primary
+            // paste entirely inside the editor.
+            m_swallowMiddleRelease = true;
+            return true;
         }
         if (mev->button() == Qt::LeftButton && inView) {
             m_leftDownInView = true; // anchor set; selection proceeds normally

src/plugin/ollieplugin.h

@@ -90,6 +90,7 @@ private:
     QHash<int, int> m_buttonToRadial; // Qt::MouseButton (int) -> def index
     bool m_gestureActive = false;     // an RMB drag gesture is in progress
     bool m_leftDownInView = false;    // LMB held inside the view (Acme chord anchor)
+    bool m_swallowMiddleRelease = false; // swallow the release paired with a consumed middle press
     QHash<QString, QPointer<QAction>> m_actionsById;
 };