gui: do word select ourselves on double-click

The overlay MouseArea swallows the B1 double-click, so returning
mouse.accepted=false did not make the TextEdit perform its native
word select — a non-delimiter double-click selected nothing. Now the
handler selects the word directly via selectWordAt when no bracket or
quote pair is under the cursor, so double-click is deterministic:
delimiter -> pair select, otherwise -> word select.

kde/gui/ChatBlockDelegate.qml

@@ -221,12 +221,13 @@ Column {
 
                 onDoubleClicked: function(mouse) {
                     if (mouse.button === Qt.LeftButton) {
-                        // Try bracket-pair selection; fall through to word select if no bracket
-                        if (selectBracketPair(mainTextEdit, mouse.x, mouse.y)) {
-                            mouse.accepted = true
-                        } else {
-                            mouse.accepted = false // let TextEdit do word select
+                        // Delimiter under cursor: select the pair.
+                        // Otherwise select the word ourselves (the overlay
+                        // swallows the event, so TextEdit won't do it).
+                        if (!selectBracketPair(mainTextEdit, mouse.x, mouse.y)) {
+                            selectWordAt(mainTextEdit, mouse.x, mouse.y)
                         }
+                        mouse.accepted = true
                     }
                 }
 
@@ -382,6 +383,27 @@ Column {
         }
     }
 
+    // Select the plain word under the mouse (double-click word select).
+    // Uses a word charset, not acme's broader isfilec, so a double-click
+    // behaves like a normal editor word select.
+    function selectWordAt(textEdit, mouseX, mouseY) {
+        var cursorPos = textEdit.positionAt(mouseX, mouseY)
+        var text = textEdit.getText(0, textEdit.length)
+        if (cursorPos < 0 || cursorPos > text.length) return
+
+        function isword(ch) {
+            return /[A-Za-z0-9_]/.test(ch)
+        }
+
+        var start = cursorPos
+        while (start > 0 && isword(text.charAt(start - 1))) start--
+        var end = cursorPos
+        while (end < text.length && isword(text.charAt(end))) end++
+
+        if (start === end) return
+        textEdit.select(start, end)
+    }
+
     // Bracket pairs for double-click selection
     function matchingBracket(ch) {
         switch (ch) {
@@ -545,11 +567,10 @@ Column {
 
                 onDoubleClicked: function(mouse) {
                     if (mouse.button === Qt.LeftButton) {
-                        if (selectBracketPair(textEdit, mouse.x, mouse.y)) {
-                            mouse.accepted = true
-                        } else {
-                            mouse.accepted = false
+                        if (!selectBracketPair(textEdit, mouse.x, mouse.y)) {
+                            selectWordAt(textEdit, mouse.x, mouse.y)
                         }
+                        mouse.accepted = true
                     }
                 }