[bug]: quota update prefills a storage limit its own form rejects

## Description

`harbor quota update` prefills the interactive form with the quota's current storage limit. The prefilled value is always a decimal string, but the "Quota Limit" input validates with `strconv.ParseInt`, so the default it hands the user is never accepted.

`pkg/views/quota/update/view.go` builds the default from `BytesToStorageString`, which formats the limit as `"%.1f GiB"` or `"%.2f MiB"`:

```go
rawStorage := list.BytesToStorageString(quta.Hard["storage"])
storagearr := strings.Split(rawStorage, " ")
...
value = storagearr[0] // "50.0"
```

and then validates it with:

```go
intval, err := strconv.ParseInt(str, 10, 64)
if err != nil {
return errors.New("Quota limit must be a valid integer")
}
```

`ParseInt("50.0")` fails, so submitting the form without editing the field always errors out. This holds for every possible limit, not just some:

| hard limit (bytes) | BytesToStorageString | prefilled value | accepted by the form |
|---|---|---|---|
| -1 (unlimited) | `-0.00 MiB` | `-0.00` | no |
| 0 | `0.00 MiB` | `0.00` | no |
| 536870912 (512 MiB) | `512.00 MiB` | `512.00` | no |
| 1073741824 (1 GiB) | `1.0 GiB` | `1.0` | no |
| 53687091200 (50 GiB) | `50.0 GiB` | `50.0` | no |

A second problem is visible in the same table: a project with an unlimited quota (`hard["storage"] == -1`) is reported as `current storage: -0.00 MiB`. The quota list view already special-cases `-1` and prints `Unlimited`; the update view does not.

## Steps to Reproduce

1. Pick a project with a storage quota set, e.g. 50 GiB.
2. Run the interactive update path (no `--storage` flag):

```bash
harbor quota update --project-name
```

3. Leave the prefilled "Quota Limit" value as-is and press Enter.

## Expected Behavior

The prefilled limit is a value the form accepts, so confirming an unchanged form is a no-op rather than an error. An unlimited quota is reported as `Unlimited`.

## Actual Behavior

The form rejects its own default with `Quota limit must be a valid integer`. The user has to clear the field and retype the number. An unlimited quota is reported as `current storage: -0.00 MiB`.

## Environment

- OS: macOS
- Tool version: Harbor CLI from `main` (d98afec)
- Other relevant details: reproduced against the current `origin/main` implementation

## Additional Context

Related, in the same function:

- `storageUnit := storagearr[1]` indexes the split result without a length check. It is safe today only because `BytesToStorageString` always emits a space, so it is a latent index-out-of-range rather than an active one.
- `fmt.Printf("current storage: %v", rawStorage)` has no trailing newline, so the form renders on the same line as the message.

I'd like to work on this.

Start in pkg/views/quota/update/view.go and trace how BytesToStorageString supplies the interactive form's default and how the Quota Limit validator parses it. Reproduce with harbor quota update --project-name , then confirm an unchanged limit is accepted and an unlimited quota is displayed as Unlimited without the formatting issues described.

Written by the indexing model from the issue text.