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/sandbox/index.ts

@@ -211,7 +211,7 @@ export default function (pi: ExtensionAPI) {
 	pi.registerTool({
 		...localBash,
 		label: "bash (sandboxed)",
-		async execute(id, params, onUpdate, _ctx, signal) {
+		async execute(id, params, signal, onUpdate, _ctx) {
 			if (!sandboxEnabled || !sandboxInitialized) {
 				return localBash.execute(id, params, signal, onUpdate);
 			}