fix: missing closing paren in debug ref.put

app/src/main/java/com/nonvioce/ijs/McpServer.java

@@ -1068,7 +1068,7 @@ public class McpServer extends NanoHTTPD {
             ref.put("_usage", "Use via the 'evaluate' tool with these expression prefixes");
             ref.put("__open", "Open a fullscreen plugin in the WebView console. Usage: evaluate('__open plugin_id'). Example: evaluate('__open power_of_two')");
             ref.put("__eval", "Execute JavaScript in WebView context. Result arrives via MCP event sync (~1 second delay). Use double quotes for strings. Example: evaluate('__eval JSON.stringify({w:IJS.canvas.width()})')");
-            ref.put("__key", "Simulate a calculator key press. Requires an open fullscreen plugin. Keys: 2, +, -, *, /, ^, (, ), =, del, c. Example: evaluate('__key 2')
+            ref.put("__key", "Simulate a calculator key press. Requires an open fullscreen plugin. Keys: 2, +, -, *, /, ^, (, ), =, del, c. Example: evaluate('__key 2')");
             ref.put("__tap", "Simulate touch at canvas logical coordinates. Requires an open fullscreen plugin. Example: evaluate('__tap 300 235')");
             ref.put("_workflow", "1. evaluate('__open plugin_id') → 2. evaluate('__tap x y') or evaluate('__key 2') → 3. evaluate('__eval console.log(\"debug\")'). Results from __eval come through regular MCP event polling.");
             ref.put("_note", "Debug commands bypass Symja evaluation. Non-debug expressions are evaluated normally.");