ci: fix snowbridge relay volume leak (#168)

## Summary

Each E2E run pulls `datahavenxyz/snowbridge-relay:latest` via `docker
create`. Because the image declares an anonymous `VOLUME`, Docker
allocates a new named volume for every run. We were removing the temp
container without `-v`, so the volume stayed on disk. After ~2,048 runs,
Docker refused to allocate new locks and aborted with exit code 125:

<img width="1425" height="86" alt="2025-09-16_18-01-06"
src="https://github.com/user-attachments/assets/ca05ac54-512d-4fa9-871c-e0b259071019"
/>

## Fix
- update `.github/workflows/task-e2e.yml` to use `docker rm -fv temp`,
ensuring the anonymous volume is removed when the temp container is
deleted

---------

Co-authored-by: Steve Degosserie <723552+stiiifff@users.noreply.github.com>

.github/workflows/task-e2e.yml

@@ -127,7 +127,7 @@ jobs:
           mkdir -p tmp/bin
           docker cp temp:/usr/local/bin/snowbridge-relay tmp/bin/
           chmod +x tmp/bin/snowbridge-relay
-          docker rm temp
+          docker rm -fv temp
           tmp/bin/snowbridge-relay --help
       
       - name: Pull DataHaven node image