feat: resizable chat panel (compact → half-right → half-left → full)

4 size modes cycled via expand button in header:
- Compact: 360px (default, bottom-right corner)
- Half-right: 50vw docked to right edge, full height
- Half-left: 50vw docked to left edge, full height
- Full: 100% viewport overlay

Also fixes text overflow in chat messages (overflow-wrap, word-break).
Messages area expands to fill available height in larger modes.
Size button uses mdi icons: arrow-expand, dock-right, dock-left, arrow-collapse.
CSS transitions for smooth size changes.

templates/partials/widgets/chat-widget.html

@@ -15,6 +15,10 @@
     <div class="chat-header">
         <iconify-icon icon="mdi:robot-happy-outline"></iconify-icon>
         <span>{{if eq .Lang "es"}}Asistente del CV{{else}}CV Assistant{{end}}</span>
+        <button class="chat-size-btn" onclick="cycleChatSize()"
+            aria-label="{{if eq .Lang "es"}}Cambiar tamaño{{else}}Resize{{end}}">
+            <iconify-icon icon="mdi:arrow-expand" id="chat-size-icon"></iconify-icon>
+        </button>
         <button class="chat-help-btn"
             aria-label="{{if eq .Lang "es"}}Ayuda{{else}}Help{{end}}"
             commandfor="chat-help-modal"
@@ -112,6 +116,21 @@ function closeChatHelpAndAsk(question) {
     sendChatQuestion(question);
 }
 
+// Cycle chat panel size: compact → half-right → half-left → full → compact
+var chatSizes = ['', 'chat-half-right', 'chat-half-left', 'chat-full'];
+var chatSizeIcons = ['mdi:arrow-expand', 'mdi:dock-right', 'mdi:dock-left', 'mdi:arrow-collapse'];
+var chatSizeIndex = 0;
+function cycleChatSize() {
+    var panel = document.getElementById('chat-panel');
+    var icon = document.getElementById('chat-size-icon');
+    // Remove current size class
+    chatSizes.forEach(function(cls) { if (cls) panel.classList.remove(cls); });
+    // Next size
+    chatSizeIndex = (chatSizeIndex + 1) % chatSizes.length;
+    if (chatSizes[chatSizeIndex]) panel.classList.add(chatSizes[chatSizeIndex]);
+    icon.setAttribute('icon', chatSizeIcons[chatSizeIndex]);
+}
+
 // Navigate from chat link to CV section, then highlight
 function scrollToCV(link) {
     var anchor = link.getAttribute('href');