fix(cli): handle session.error in run command to prevent infinite wait

When session.error occurs with incomplete todos, the run command now:
- Captures the error via handleSessionError()
- Exits with code 1 instead of waiting indefinitely
- Shows clear error message to user

Previously, run command ignored session.error events, causing infinite
'Waiting: N todos remaining' loop when agent errors occurred.

🤖 Generated with assistance of OhMyOpenCode
https://github.com/code-yeongyu/oh-my-opencode

src/cli/run/events.test.ts

@@ -74,6 +74,8 @@ describe("event handling", () => {
     const ctx = createMockContext("my-session")
     const state: EventState = {
       mainSessionIdle: true,
+      mainSessionError: false,
+      lastError: null,
       lastOutput: "",
       lastPartText: "",
       currentTool: null,