move INV button from footer into channel delegate rows (second button left of plus)

tools/chatgui/src/channeldelegate.cpp

@@ -12,6 +12,13 @@ QRect ChannelDelegate::inviteButtonRect(const QRect &itemRect) {
                  InviteBtnSize, InviteBtnSize);
 }
 
+QRect ChannelDelegate::inviteByLinkButtonRect(const QRect &itemRect) {
+    const int margin = 6;
+    return QRect(itemRect.right() - margin - InviteBtnSize * 2 - InviteBtnGap,
+                 itemRect.bottom() - margin - InviteBtnSize,
+                 InviteBtnSize, InviteBtnSize);
+}
+
 void ChannelDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
                             const QModelIndex &index) const {
     painter->save();
@@ -169,6 +176,29 @@ void ChannelDelegate::paint(QPainter *painter, const QStyleOptionViewItem &optio
     painter->drawLine(plusRect.left() + 5, plusRect.center().y(),
                       plusRect.right() - 5, plusRect.center().y());
 
+    /* ── invite-by-link button (left of plus, orange square with arrow) ── */
+    QRect invRect = inviteByLinkButtonRect(option.rect);
+    bool invHovered = index.data(ChannelInviteByLinkBtnHoveredRole).toInt() != 0;
+    painter->setRenderHint(QPainter::Antialiasing);
+    if (invHovered) {
+        painter->setBrush(QColor(0xE6, 0x7E, 0x22));
+        painter->setPen(Qt::NoPen);
+        painter->drawRoundedRect(invRect, 3, 3);
+        painter->setPen(QPen(Qt::white, 1.5));
+    } else {
+        painter->setBrush(QColor(0xE6, 0x7E, 0x22, 110));
+        painter->setPen(Qt::NoPen);
+        painter->drawRoundedRect(invRect, 3, 3);
+        painter->setPen(QPen(QColor(0xE6, 0x7E, 0x22), 1.5));
+    }
+    /* arrow pointing into a box: →| or a simple arrow-left: ← */
+    int cx = invRect.center().x(), cy = invRect.center().y();
+    int dx = 3;
+    painter->drawLine(cx + dx, cy - 3, cx - dx, cy);
+    painter->drawLine(cx + dx, cy + 3, cx - dx, cy);
+    painter->drawLine(cx + dx + 1, cy, cx + dx + 1, cy - 3 + 1);
+    painter->drawLine(cx + dx + 1, cy, cx + dx + 1, cy + 3 - 1);
+
     painter->restore();
 }