Add shared Infisical auth layer (InfisicalConnection + InfisicalAuth)

Phase 2: GitOps-managed shared auth layer in infisical-operator ns —
InfisicalConnection (https://infisical.chemavx.xyz) + InfisicalAuth
(kubernetes method, operator SA via TokenReview) + identity-ID Secret
(non-secret UUID; auth is via SA token, so safe in git). To be referenced
cross-namespace by per-app InfisicalStaticSecret CRs later. No real secret yet.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

infisical-config/secret-machine-identity.yaml

@@ -0,0 +1,11 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: infisical-machine-identity
+  namespace: infisical-operator
+type: Opaque
+stringData:
+  # Non-secret UUID for machine identity "k8s-operator". Required as a secretRef
+  # by the InfisicalAuth schema; auth happens via the operator's SA token (TokenReview),
+  # so this value grants nothing on its own. Safe to commit.
+  identityId: "42c12566-1058-4674-a5f5-0cc1bc0ea4e7"