Assisted FluxCD apply

[RealityAnomaly]

Provide a mechanism to do an "assisted FluxCD" apply, on top of a future manual implementation of a system that directly uses the Kubernetes API to apply the resources and manages dependency gates (#10). This would require a reference to a local Git repo on-disk (or we could internalise the cloning and pushing of it?)

1. Enlighten the diff functionality so diffs can run against the cluster itself
2. Add the resource files to the Git repo, stage the changes, commit, and push
3. Set the annotation via Flux to force an immediately scheduled pull
4. Watch resources and report the progress of the apply to the user
5. Respond with a success/failure