GKE: app registry and bootstrap Application for gke-toolshed-prd-usc1

Adds the GCP counterpart of the homelab's cluster entry point, alongside
it rather than replacing it, so the two clusters never share a values
file:

- values/incubator-infra-gke-toolshed-prd-usc1-values.yaml, starting with
  only argocd, gitea and cert-manager. Every appSpec entry's nameOverride
  equals the Helm release name each is installed under by hand, which is
  what makes ArgoCD adopt those releases instead of rendering a second
  copy of each.
- incubator/incubator-infra-gke-toolshed-prd-usc1.yaml, the parent
  Application, applied once by hand.
- app-of-projects.yaml and the devops AppProject now point at this
  cluster's Gitea over cluster DNS, not the homelab's LAN hostname.

Sources are reached at gitea-http.gitea.svc.cluster.local:3000 rather
than through an Ingress: ArgoCD has to read them before Contour exists,
since Contour is itself one of the Applications it installs.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LEsTefWWifp4ikvhHF5s6N

incubator/incubator-infra-gke-toolshed-prd-usc1.yaml

@@ -0,0 +1,19 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: incubator-infra-gke-toolshed-prd-usc1
+  namespace: argocd
+  finalizers:
+    - resources-finalizer.argocd.argoproj.io
+spec:
+  project: default
+  source:
+    repoURL: 'http://gitea-http.gitea.svc.cluster.local:3000/gitadmin/devops-infra-argo-config-gcp.git'
+    targetRevision: main
+    path: generic-argo-apps-chart
+    helm:
+      valueFiles:
+      - ../values/incubator-infra-gke-toolshed-prd-usc1-values.yaml
+  destination:
+    name: in-cluster
+    namespace: argocd