Make org links in headline titles clickable

Headline titles were rendered as plain text, so an inline org link in a
heading showed its raw [[target][desc]] syntax and could not be followed.
Body text and list items already route links through renderInline and
onLinkActivated; apply the same treatment to the title Label.

The title now renders as StyledText via renderInline, exposes a pointer
cursor over links through a HoverHandler, and dispatches clicks to
openLink (which resolves and navigates via the model). Non-link text
keeps its done-aware color and strike-through.

ui/qml/OutlineView.qml

@@ -361,14 +361,24 @@ ListView {
                     font.bold: true
                 }
 
-                // Title
+                // Title. Rendered as StyledText so inline org links in the
+                // headline are clickable; non-link text keeps the done-aware
+                // color and strike-through.
                 Label {
-                    text: del.model.title ?? ""
+                    text: outline.renderInline(del.model.title ?? "")
                     color: (del.model.isDone ?? false) ? theme.placeholderTextColor : theme.textColor
+                    linkColor: theme.linkColor
                     font.pointSize: outline.levelFontSize(del.sectionLevel)
                     font.strikeout: del.model.isDone ?? false
                     elide: Text.ElideRight
                     Layout.fillWidth: true
+                    textFormat: Text.StyledText
+                    onLinkActivated: (link) => outline.openLink(link)
+
+                    HoverHandler {
+                        enabled: parent.hoveredLink !== ""
+                        cursorShape: Qt.PointingHandCursor
+                    }
                 }
 
                 // Scheduled timestamp