fix(tui): handle race condition when agents array is empty during initialization

[WhiteElephantIsNotARobot]

Summary

Fixes TypeError: undefined is not an object (evaluating 'local.agent.current().name')

This is a widespread issue (13+ duplicate issues reported) that occurs when the app starts before agents are fetched from the API.

Root Cause

Race condition between SyncProvider and LocalProvider initialization:

1. SyncProvider starts with empty agent: []
2. LocalProvider initializes immediately and tries to access agents()[0].name
3. agents() returns [], so agents()[0] is undefined
4. Accessing .name on undefined throws the TypeError

Changes

local.tsx

• Changed agentStore.current type to string | undefined
• Use optional chaining (agents()[0]?.name) for initialization
• Updated current() to return undefined when no agents available
• Added null checks in move(), cycle(), cycleFavorite(), set(), and createEffect

prompt/index.tsx

• Added null check for agent.current() in submit() function
• Updated createMemo functions to handle undefined agent

dialog-agent.tsx

• Use optional chaining for agent.current()?.name

Test Plan

• Start the application without any agents configured
• Verify the app doesn't crash with the TypeError
• Verify agents are loaded correctly once the API responds
• Verify normal operation continues after agents are loaded

Fixes#11096

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential Duplicate PRs Found

I found several related PRs that address the same underlying issue - handling undefined agent.current():

1. PR fix(tui): handle undefined agent.current() to prevent fatal TypeError #7689 - fix(tui): handle undefined agent.current() to prevent fatal TypeError

   • Directly addresses the TypeError mentioned in PR fix(tui): handle race condition when agents array is empty during initialization #11100

2. PR fix(tui): handle undefined agent.current() to prevent crash on startup #7748 - fix(tui): handle undefined agent.current() to prevent crash on startup

   • Specifically targets the startup crash scenario

3. PR fix(opencode): add null checks for agent.current() in prompt #7920 - fix(opencode): add null checks for agent.current() in prompt

   • Adds null safety checks in the prompt component

4. PR fix(tui): add null safety for local.agent.current().name (#8858) #8882 - fix(tui): add null safety for local.agent.current().name (#8858)

   • Adds null safety specifically for the .name property access

These PRs all appear to be attempting to fix similar or related issues with the same TypeError. Your PR #11100 may be addressing a recurring issue that has been attempted multiple times before. It would be worth investigating whether these previous PRs were merged or if there's a reason this issue is still occurring.