Deploy bind-operator (operator + CRDs) (#219)

First of a 4-PR split of the bind rollout (was #216). Deploys just the operator control plane so it can be verified before any DNS clusters exist.

## Why
Roll out incrementally: operator + CRDs first, then each BIND tier as its own PR.

## Changes
- `apps/base/bind-system`: operator Deployment (`git.unkin.net/unkin/bind-operator:v0.1.1`), RBAC, namespace; CRDs pulled from the operator repo by raw URL (`config/crd/install.yaml` @ v0.1.1)
- au-syd1 `bind-system` overlay
- register all four bind apps in `argocd/applicationsets/platform.yaml` (DNS overlays instantiate only when their dirs land in the follow-up PRs)
- add `binddns-*` namespaces to `argocd/projects/platform.yaml`
- add `schemas/bind.unkin.net/*.json` for kubeconform

## Deploy impact
Operator pod + CRDs only. No DNS services yet — the operator is idle until BindClusters exist.

## Follow-ups (merge after this)
binddns-auth, binddns-resolver, binddns-externaldns — one PR each.

Reviewed-on: #219
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

argocd/applicationsets/platform.yaml

@@ -12,6 +12,10 @@ spec:
       directories:
       - path: apps/overlays/*/authentik
       - path: apps/overlays/*/artifactapi
+      - path: apps/overlays/*/bind-system
+      - path: apps/overlays/*/binddns-auth
+      - path: apps/overlays/*/binddns-resolver
+      - path: apps/overlays/*/binddns-externaldns
       - path: apps/overlays/*/age-api
       - path: apps/overlays/*/cattle-system
       - path: apps/overlays/*/cert-manager

argocd/projects/platform.yaml

@@ -21,6 +21,12 @@ spec:
       server: https://kubernetes.default.svc
     - namespace: 'authentik'
       server: https://kubernetes.default.svc
+    - namespace: 'binddns-auth'
+      server: https://kubernetes.default.svc
+    - namespace: 'binddns-resolver'
+      server: https://kubernetes.default.svc
+    - namespace: 'binddns-externaldns'
+      server: https://kubernetes.default.svc
     - namespace: 'cert-manager'
       server: https://kubernetes.default.svc
     - namespace: 'certificates'