feat: this estate's n8n deployment

The values that infra-n8n deliberately does not carry: our hostname, issuer,
Vault path and images, plus the two things that are ours alone — the lab CA the
workflows need to verify internal TLS, and the agents' Keycloak client secrets,
read from the realm's own Vault entry so there is one source per secret.

Self-managing after three applies, like the rest of the estate.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

deploy/gitrepository.yaml

@@ -0,0 +1,13 @@
+# The generic n8n deployment template. It carries no value specific to this
+# estate — every hostname, issuer and Vault path comes from the substitutions
+# in flux-kustomization.yaml beside this file.
+apiVersion: source.toolkit.fluxcd.io/v1
+kind: GitRepository
+metadata:
+  name: infra-n8n
+  namespace: n8n
+spec:
+  interval: 5m
+  url: https://gitea.sttlab.eu/stt/infra-n8n.git
+  ref:
+    branch: main