feat(coding-agent): expose deliverAs option in hook sendMessage() API

- pi.sendMessage(msg, options?) now accepts { triggerTurn?, deliverAs? }
- deliverAs: 'steer' (default) or 'followUp' controls delivery timing
- Update all mode handlers to pass options through
- Update file-trigger example to use new API
- Update CHANGELOG

packages/coding-agent/examples/hooks/file-trigger.ts

@@ -25,7 +25,7 @@ export default function (pi: HookAPI) {
 							content: `External trigger: ${content}`,
 							display: true,
 						},
-						true, // triggerTurn - get LLM to respond
+						{ triggerTurn: true }, // triggerTurn - get LLM to respond
 					);
 					fs.writeFileSync(triggerFile, ""); // Clear after reading
 				}