fix(coding-agent): align ToolDefinition.execute signature with AgentTool

BREAKING CHANGE: ToolDefinition.execute parameter order changed from
(id, params, onUpdate, ctx, signal) to (id, params, signal, onUpdate, ctx).

This aligns with AgentTool.execute so wrapping built-in tools no longer
requires parameter reordering. Update extensions by swapping signal and
onUpdate parameters.

packages/coding-agent/examples/extensions/bash-spawn-hook.ts

@@ -23,7 +23,7 @@ export default function (pi: ExtensionAPI) {
 
 	pi.registerTool({
 		...bashTool,
-		execute: async (id, params, onUpdate, _ctx, signal) => {
+		execute: async (id, params, signal, onUpdate, _ctx) => {
 			return bashTool.execute(id, params, signal, onUpdate);
 		},
 	});