chore: drop evolution-manager-v2 submodule

The manager-v2 source repository is now private, so the CI checkout step
fails when trying to fetch the submodule (no PAT configured, GITHUB_TOKEN
has no cross-repo read scope). Drop the submodule entirely — the runtime
artefact already lives under manager/dist/ in this repo, which is what
the Express server serves. Source for the manager continues to be
maintained at evolution-foundation/evolution-manager-v2 (private).

Author: DavidsonGomes