Render org links in the GUI body

Body text and list items now render org links ([[target]] and
[[target][description]]) as clickable hyperlinks via StyledText. Other
text is HTML-escaped and newlines become <br> so formatting is preserved.

Activating a link opens external URL schemes (http(s), mailto, file) in
the system handler; internal links (id:, #custom, *headline) are left for
a future navigation pass. The pointer cursor shows over hovered links.

ui/qml/OutlineView.qml

@@ -41,6 +41,45 @@ ListView {
         return Math.max(outline.baseFontSize - 1, outline.baseFontSize + 5 - level)
     }
 
+    // Escape HTML special chars for safe StyledText rendering.
+    function escHtml(s) {
+        return String(s)
+            .replace(/&/g, "&")
+            .replace(/</g, "&lt;")
+            .replace(/>/g, "&gt;")
+    }
+
+    // Render inline org markup (currently links) to StyledText. Org links are
+    // [[target]] or [[target][description]]; everything else is escaped. Line
+    // breaks are converted to <br> so StyledText preserves them.
+    function renderInline(text) {
+        let re = /\[\[([^\]\[]+?)\](?:\[([^\]]*?)\])?\]/g
+        let out = ""
+        let last = 0
+        let m
+        function escBlock(s) { return escHtml(s).replace(/\n/g, "<br>") }
+        while ((m = re.exec(text)) !== null) {
+            out += escBlock(text.slice(last, m.index))
+            let target = m[1]
+            let desc = (m[2] !== undefined && m[2] !== "") ? m[2] : m[1]
+            let href = escHtml(target).replace(/"/g, "&quot;")
+            out += '<a href="' + href + '">' + escHtml(desc) + '</a>'
+            last = re.lastIndex
+        }
+        out += escBlock(text.slice(last))
+        return out
+    }
+
+    // Open a link target activated from body text. External URL schemes open
+    // in the system handler; internal org links (id:, #custom, *headline) are
+    // left for a future navigation pass.
+    function openLink(target) {
+        if (/^([a-zA-Z][a-zA-Z0-9+.-]*):\/\//.test(target)
+                || /^(mailto:|file:)/.test(target)) {
+            Qt.openUrlExternally(target)
+        }
+    }
+
     delegate: Rectangle {
         id: del
         width: outline.width
@@ -427,12 +466,19 @@ ListView {
                                 }
                                 Label {
                                     Layout.fillWidth: true
-                                    text: modelData.content
+                                    text: outline.renderInline(modelData.content)
                                     color: theme.placeholderTextColor
+                                    linkColor: theme.linkColor
                                     font.pointSize: outline.baseFontSize + 1
                                     lineHeight: 1.3
                                     wrapMode: Text.WordWrap
-                                    textFormat: Text.PlainText
+                                    textFormat: Text.StyledText
+                                    onLinkActivated: (link) => outline.openLink(link)
+
+                                    HoverHandler {
+                                        enabled: parent.hoveredLink !== ""
+                                        cursorShape: Qt.PointingHandCursor
+                                    }
                                 }
                             }
                         }
@@ -497,13 +543,20 @@ ListView {
                                         // Item text; checked items are dimmed and struck through.
                                         Label {
                                             Layout.fillWidth: true
-                                            text: modelData.text ?? ""
+                                            text: outline.renderInline(modelData.text ?? "")
                                             color: (modelData.checkbox === "checked")
                                                    ? theme.placeholderTextColor : theme.textColor
+                                            linkColor: theme.linkColor
                                             font.pointSize: outline.baseFontSize + 1
                                             font.strikeout: modelData.checkbox === "checked"
                                             wrapMode: Text.WordWrap
-                                            textFormat: Text.PlainText
+                                            textFormat: Text.StyledText
+                                            onLinkActivated: (link) => outline.openLink(link)
+
+                                            HoverHandler {
+                                                enabled: parent.hoveredLink !== ""
+                                                cursorShape: Qt.PointingHandCursor
+                                            }
                                         }
                                     }
                                 }