feat(desktop): performance and clipboard pages, a scrolling tile grid

The tile grid sits in a Flickable capped at three rows, so the fourth row
the new modules bring scrolls inside that box instead of eating the
notification space; a thin accent bar in the margin shows only when a row
is hidden. Tiles are reordered with the everyday ones first.

Performance shows the island's PerfPanel in a Page, with a tile line of CPU
and RAM and the warning dot. Perf.detailed is now a count of live PerfPanel
instances instead of a binding in the status pill: the island and the drawer
both host the panel, and a bool with two writers would let one clear it
under the other.

Clipboard reads cliphist when its page opens: search, copy on click or
Enter, delete per row, clear all behind a 3 second confirm, image entries as
thumbnails decoded once onto tmpfs. Entries reach sh as $1, never inside a
command string. A copy closes the drawer through a new Page.dismiss signal
the drawer connects like back.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 48 insertions, 21 deletions

diff --git a/desktop/Drawer.qml b/desktop/Drawer.qml
index 31067f8..4285506 100644
--- a/desktop/Drawer.qml
+++ b/desktop/Drawer.qml
@@ -153,34 +153,58 @@ Scope {
                     NotificationList {
                         id: notifications
                         anchors { top: parent.top; left: parent.left; right: parent.right }
-                        anchors.bottom: grid.top
+                        anchors.bottom: tiles.top
                         anchors.bottomMargin: 16
                         onHistory: root.history = true
                     }
 
-                    // Fixed, never scrolled. Three columns at 600px with a
-                    // 180px minimum; tiles wrap and add rows, ceiling 3x3.
-                    Flow {
-                        id: grid
+                    // At most three rows tall; more tiles scroll inside
+                    // this box, so the notification space above never
+                    // shrinks when a module is added.
+                    Flickable {
+                        id: tiles
                         anchors { left: parent.left; right: parent.right; bottom: parent.bottom }
-                        spacing: 10
-
-                        Repeater {
-                            model: root.modules
-
-                            Tile {
-                                required property QtObject modelData
-                                // Three columns, or fewer if the panel is
-                                // narrower than three 180px tiles allow.
-                                width: (grid.width - 2 * grid.spacing) / 3
-                                icon: modelData.icon
-                                label: modelData.label
-                                active: modelData.active
-                                content: modelData.tileContent
-                                onClicked: root.activate(modelData)
+                        readonly property int maxRows: 3
+                        height: Math.min(grid.height, maxRows * 96 + (maxRows - 1) * grid.spacing)
+                        contentHeight: grid.height
+                        clip: true
+                        boundsBehavior: Flickable.StopAtBounds
+
+                        Flow {
+                            id: grid
+                            width: tiles.width
+                            spacing: 10
+
+                            Repeater {
+                                model: root.modules
+
+                                Tile {
+                                    required property QtObject modelData
+                                    // Three columns, or fewer if the panel is
+                                    // narrower than three 180px tiles allow.
+                                    width: (grid.width - 2 * grid.spacing) / 3
+                                    icon: modelData.icon
+                                    label: modelData.label
+                                    active: modelData.active
+                                    content: modelData.tileContent
+                                    onClicked: root.activate(modelData)
+                                }
                             }
                         }
                     }
+
+                    // A thin bar in the panel margin, there only when a row
+                    // is hidden, so the fourth row is discoverable. Outside
+                    // the Flickable, whose clip would hide it.
+                    Rectangle {
+                        visible: tiles.contentHeight > tiles.height
+                        anchors { left: tiles.right; leftMargin: 6 }
+                        y: tiles.y + tiles.visibleArea.yPosition * tiles.height
+                        width: 3
+                        height: tiles.visibleArea.heightRatio * tiles.height
+                        radius: 1.5
+                        color: Qt.alpha(Theme.accent, 0.6)
+                    }
                 }
 
                 // --- page view ---
@@ -195,7 +219,10 @@ Scope {
                     // The Page's back arrow returns to the grid. Without this
                     // the header button is inert, since the page only emits
                     // `back` and does not know who hosts it.
-                    onLoaded: if (item && item.back) item.back.connect(() => root.page = "")
+                    onLoaded: {
+                        if (item && item.back) item.back.connect(() => root.page = "");
+                        if (item && item.dismiss) item.dismiss.connect(root.close);
+                    }
 
                     // The page header shows the module's tile glyph. A Binding,
                     // not an assignment in onLoaded, so a module whose icon