Improve discoverability of Usage Limits in the UI

[eduardozf]

T3 Code already has a really useful Limits view under Usage → Limits, showing the remaining provider limits and reset times.

The problem is that it's quite easy to miss.

Once you know where it is, the location makes sense. But for a new user, there's very little indication that T3 Code can show this information at all. I've seen multiple people ask for a limits/usage-limit feature without realizing that it already exists.

A few examples from X:

1. https://x.com/MarkLyck/status/2098440602224308713
2. https://x.com/BearHuddleston/status/2097132155918831797
3. https://x.com/duzferraz/status/2097138889584423306 ^{(That's me)}
4. https://x.com/JeroenB_4/status/2097459056180908285 ^Similar
5. https://x.com/niclas__4/status/2098444946495746527 ^Similar
6. https://x.com/gusbsmith/status/2097381345756406169 ^{Similar; We should not explain that}

And I bet there are people using T3 Code right now who still don't know this view exists.

I think this is a good signal that the issue isn't the feature itself, but feature discoverability.

[juliusmarminge]

Changed it to be the default tab in #11261