Incorrect disk size reported when running in Docker on macOS

Running the agent in Docker Desktop on macOS (Sonoma). Disk mountpoints are configured correctly and the container can see the real filesystem, but the sizes reported in the widget are wildly incorrect.

**docker-compose.yml**
```yaml
services:
glance-agent:
container_name: glance-agent
image: glanceapp/agent
environment:
TOKEN: ""
HIDE_MOUNTPOINTS_BY_DEFAULT: "true"
MOUNTPOINTS: "/host-data:Macintosh HD"
volumes:
- /System/Volumes/Data:/host-data:ro
ports:
- 27973:27973
restart: unless-stopped
```

**`df -h` inside the container shows the mount is correct**
```
/run/host_mark/System/Volumes/Data 2.8T 88.1G 2.8T 3% /host-data
```

**But the widget reports**
```
Macintosh HD — 23.1 TB / 762.1 TB
```