fix(web): keep chat context menu within viewport

- adjust right-click menu coordinates to avoid clipping near screen edges

web/src/components/ChatList.tsx

@@ -84,8 +84,9 @@ export function ChatList() {
             onClick={() => setActiveChatId(chat.id)}
             onContextMenu={(e) => {
               e.preventDefault();
+              const safePos = getSafeContextPosition(e.clientX, e.clientY);
               setCtxChatId(chat.id);
-              setCtxPos({ x: e.clientX, y: e.clientY });
+              setCtxPos(safePos);
             }}
           >
             <div className="flex items-start gap-3">
@@ -155,3 +156,11 @@ export function ChatList() {
     </aside>
   );
 }
+  function getSafeContextPosition(x: number, y: number): { x: number; y: number } {
+    const menuWidth = 176;
+    const menuHeight = 56;
+    const pad = 8;
+    const safeX = Math.min(Math.max(pad, x), window.innerWidth - menuWidth - pad);
+    const safeY = Math.min(Math.max(pad, y), window.innerHeight - menuHeight - pad);
+    return { x: safeX, y: safeY };
+  }