fix(prompt): open slash menu when typing / anywhere

[lucaslopesx]

Issue for this PR

Closes #16826

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

The slash command menu only opened when / was typed as the first character in the prompt. Changed the slash detection to scan text before the cursor position instead of only checking if / is at index 0, allowing the menu to open anywhere in the prompt.

How did you verify your code works?

1. Open the prompt
2. Type hello
3. Type / the slash command menu now appears at the cursor

Screenshots / recordings

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

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

Found a potentially related PR:

Related PR:

• feat(app): support slash commands mid-prompt #16263 - feat(app): support slash commands mid-prompt
  • This appears to be addressing a similar issue about supporting slash commands in the middle of prompts, which is closely related to PR fix(prompt): open slash menu when typing / anywhere #16832's fix for opening the slash menu anywhere in the prompt rather than only at the start.

These PRs likely address the same feature/bug area. You may want to verify if #16263 is already merged or if it's been superseded by this new fix.