fix(ui): restrict chart types

.opencode/tools/show_chart.ts

@@ -9,7 +9,7 @@ export default tool({
       .describe("Why this chart should be rendered for the user request."),
     title: tool.schema.string().optional().describe("Chart title."),
     chart_type: tool.schema
-      .enum(["line", "bar", "pie"])
+      .enum(["line", "bar"])
       .optional()
       .describe("Chart type."),
     x_data: tool.schema

src/uiEnvelope/fromToolCall.ts

@@ -42,10 +42,7 @@ export const toUiEnvelopeFromToolCall = ({
     if (xData.length === 0 || series.length === 0) {
       return null;
     }
-    const chartType =
-      params.chart_type === "bar" || params.chart_type === "pie"
-        ? params.chart_type
-        : "line";
+    const chartType = params.chart_type === "bar" ? "bar" : "line";
     return {
       kind: "chart",
       schemaVersion: "agent-ui@1",