fix: fix login image (#10355)

# Which Problems Are Solved

The broken login image is fixed.

# How the Problems Are Solved

The most important learnings from
https://github.com/zitadel/zitadel/pull/10318 are applied:
- Path in entrypoint is fixed: `exec node /runtime/apps/login/server.js`
- .dockerignore is updated so CSS styles are built into the image
- `source: .` is passed to the docker-bake action. Without this,
docker-bake builds from a remote context, which seems to be slow and not
updated on new PR commits. Looks like the bake action uploads an
artifact that [conflicts with the compile
workflow](https://github.com/zitadel/zitadel/actions/runs/16620417216/job/47023478437).
Therefore, a pattern is added to the compile workflow so only relevant
artifacts are selected.

apps/login/scripts/entrypoint.sh

@@ -8,6 +8,4 @@ if [ -n "${ZITADEL_SERVICE_USER_TOKEN_FILE}" ] && [ -f "${ZITADEL_SERVICE_USER_T
   export ZITADEL_SERVICE_USER_TOKEN=$(cat "${ZITADEL_SERVICE_USER_TOKEN_FILE}")
 fi
 
-
-
-exec node /runtime/apps/login/apps/login/server.js
+exec node /runtime/apps/login/server.js