More precision in the usage quota bar

Here's how the quota bar is visible now:

I, as a user, would like to know: do I have enough space to upload 500GB of data?

The problem is that the quota shows only to 1 digit after the comma, which means:

Best case scenario: Quota is 3123 GB (~3.049 TB, shown as 3TB) and I'm using 2509 GB (~2.45TB, shown as 2.5TB)
I have 614GB to spare.

Worst case scenario: Quota is 3021 GB (~2.95 TB, shown a 3TB) and I'm using 2610 GB (~2.54TB, shown as 2.5TB)
I have 411GB to spare.

This example shows that there could be a significant (x1.5 times!) error when calculating the space left. And this is not a hypothetical example, I genuinely don't know that on a real Nextcloud server.

I propose we show 3 digits of precision in any case.
In addition, it might be useful to explicitly show the amount left.

So instead of:

You are using 2.5TB / 3TB

The user would see something like:

You are using 2.51TB / 3.00 TB (493 GB left)

Some more examples (current->proposed):
999GB -> 999GB
1TB -> 1.04TB
10TB -> 10.4TB

Notice that in every case I have 3 digits of precision, where in the current scheme you can have 2 or 3.

The issue does not name files or tests. Start by locating the quota bar and the existing storage-size formatting entry point, then check how remaining space is calculated and displayed. Done means the displayed used and total values retain three significant digits and the amount left is shown accurately.