Fix: allow tab auto-complete without executing

[joshbarrington]

This fixes issues:
#2257
#1819

There was another implementation for a fix here: #2275

However I expanded upon that by simplifying and removing AutoComplete from the command interface, as this was hardcoded to be always true. It is now driven by the Update function directly.

I also added some more exhaustive tests and changes suggested through mise lint.

[yunus25jmi1]

Thanks for referencing #2275 and building on it! I can see this version simplifies the implementation by moving the execute behavior into Update() directly and expands the tests as well. This looks like a cleaner approach to fix issues #2257 and #1819. I'm happy to defer to this implementation if maintainers prefer this direction. Looking forward to the review!

[krissetto]

Hey! Thanks for the contributions @joshbarrington && @yunus25jmi1

Both here and in #2275 we need to pay attention to not create regressions. As-is, this breaks the UX in other parts of the app.

Auto-complete in it's current shape is not only used for /commands, but also for things like @attachments.

With these changes:

• if a user types @ and then hits tab on Browse files.. the file picker will no longer open, the @ will disappear and a single space will be left instead. That's confusing;
• if they press enter on a file the message with the attachment gets sent immediately. That's also undesired, as the goal is to autocomplete the filename and attach it instead, not attach and send in a single action because the user might want to continue their message before sending it.

We need to think about supporting both scenarios, so /commands are a bit less annoying, and @attachments continue to work as they were designed to

Not sure who wants to take on the changes, but we're glad to get changes merged as soon as they don't unintentially break other types of auto-complete :)

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Screencast below shows the problematic behavior:

Screen.Recording.2026-04-04.at.21.37.24.mov

[krissetto]

☝️

[joshbarrington]

@krissetto Thanks for the heads up on the regression. Are there any other inputs such as the '@' symbol that we need to be aware of?