fix(cli): gracefully handle model API errors instead of crashing

When the model provider returns 503/429/5xx, the error was re-thrown
from the agent loop hook, causing the Ink process to crash and exit.

Now the error is caught and displayed as an assistant message so the
user can retry without restarting the session.

Author: c001estb0y

src/cli/tui/hooks/use-agent-loop.ts

@@ -133,7 +133,12 @@ export function AgentLoopProvider({
         }
       } catch (error) {
         if (isAbortError(error)) return;
-        throw error;
+        // Display API/model errors as assistant messages instead of crashing
+        const errorMessage = error instanceof Error ? error.message : String(error);
+        enqueueMessage({
+          role: "assistant",
+          content: [{ type: "text", text: `Error: ${errorMessage}\n\nYou can try again.` }],
+        });
       } finally {
         agent.setRequestedSkillName(null);
         flushPendingMessages();