[FEATURE] Be able to use slash commands after first character

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

I often want to put in slash commands after I type in something, to be more natural with the flow, or just since I think of it midway through. For example:

Thanks! From what I can tell, everything works now.
/make-git-commits

where /make-git-commits is a custom command I've made that has some instructions. But:

1. Typing slash doesn't open the command picker, so I'd have to remember the name
2. Even if I type it out manually in this manner, Claude doesn't seem to be able to find the actual command.

So the current behavior doesn't allow for commands with any other typing, even with whitespace present at the beginning.

Proposed Solution

When typing a slash lower down the message, it opens the slash command picker in a standard way and I can execute at least one command (if not enqueue multiple to be run, although that could be considered a separate feature.)

Alternative Solutions

I can type in things, then press esc to halt Claude processing on it, then type in a command in the standard way. But it's a bit clunky.

Priority

Medium - Would be very helpful

Feature Category

Interactive mode (TUI)

Use Case Example

This is still exhibiting the issue seen at
/github-issue-lookup 1234
So I think we need to address that

(then the agent looks up that issue based on the instructions in the slash command documentation)

Additional Context

_No response_