### What happened

The Dropbox bar widget reports the wrong storage quota for Dropbox Basic accounts that carry bonus space.

My account shows **1.53 GB of 21.38 GB** on dropbox.com, but the widget shows **1.64 GB of 2 GB** — so it renders as ~82% full when the account is actually ~7% full.

### Cause

`shell/plugins/panels/dropbox/status.py` maps the plan name to a hardcoded quota:

```python
PLAN_QUOTAS = {
  "basic": 2_000_000_000,
  "plus": 2_000_000_000_000,
  ...
}
```

```python
quota = PLAN_QUOTAS.get(plan.lower(), 0)
```

`plan` comes from `subscription_type` in `~/.dropbox/info.json`, which is just `"Basic"`. But 2 GB is only the *starting* allocation for a Basic account. Referral bonuses (500 MB each, up to 16 GB, permanent) and older promos such as the 3 GB camera-upload bonus permanently raise the real quota. Mine adds up to 21.38 GB. Nothing in the plan name conveys this, so any long-standing Basic account is misreported.

The same applies in the other direction for Plus/Professional accounts with add-on storage.

### Steps to reproduce

1. Use a Dropbox Basic account that earned referral or promo bonus space (real quota > 2 GB).
2. Log in via the Dropbox widget and let it sync.
3. Open the widget panel.
4. It reads `of 2 GB` instead of the account's actual quota, and the usage bar is proportionally wrong.

### Expected

The quota shown should match the account's real allocation, or the widget should omit the denominator when it cannot determine it, rather than assert a value it hasn't verified.

### Notes on fixing

The local daemon doesn't expose the quota — `dropbox-cli` has no such command, and `~/.dropbox/info.json` carries only the plan name. The authoritative figure comes from the Dropbox API (`/2/users/get_space_usage`, `allocation.allocated`), which needs an OAuth token, so a fully automatic fix means adding a token setup flow.

Cheaper options, in rough order of effort:

- Add an optional quota-override setting to the widget manifest so affected users can correct it (this is what I did locally, as a cloned plugin — a `quotaOverrideMB` integer setting passed through to `status.py`).
- Fall back to `quotaKnown: false` for `basic` specifically, since it's the one plan whose stated quota is routinely wrong, and show usage without a denominator.

Happy to open a PR for the override-setting approach if that direction is welcome.

### Related detail

`usedBytes` is also computed locally by `scan_dropbox()` walking the sync folder rather than read from Dropbox. It's close enough when everything is synced (1.64 GB vs 1.53 GB here, the difference being `.dropbox.cache`), but it will understate usage for anyone using selective sync. Same root cause: no API access.

### System

- Omarchy 4.0.0-1
- Dropbox 264.4.3421-1, dropbox-cli 2024.04.17-2
- Account type: Dropbox Basic with referral/promo bonus space