feat: add Helmfile-managed k8s charts for tasks 10-13

Local charts: kafka-cluster (Strimzi Kafka+KafkaNodePool CRs, 3-replica KRaft
topology, 5Gi memory cap, Longhorn storage, pod anti-affinity), queue-crd
(Queue CRD + queue-operator Deployment/RBAC), management-service
(Deployment/Service/ConfigMap/HPA/Ingress, REST exposed externally via
cert-manager-issued TLS, raw gRPC kept cluster-internal per design.md §7a).

helmfile.yaml.gotmpl + releases.d/*.gotmpl wire strimzi-operator ->
kafka-cluster -> redis -> {queue-crd, management-service} via `needs:`.
Directory is releases.d, not helmfile.d as originally sketched in design.md
section 7b: Helmfile v1 treats a literal "helmfile.d" directory as a special
auto-discovery mode that conflicts with an explicit top-level helmfile.yaml.
Files use .gotmpl (required by Helmfile v1 for {{ }}-templated files) and
each declares its own environments: block, since nested helmfiles don't
inherit the parent's resolved values in this version.

Namespace is sqs throughout. environments/homelab.yaml carries no secrets.
Validated locally via helm lint/helm template (all 3 charts) and
`helmfile -e homelab build` (dependency ordering + value substitution) — no
cluster contact made. Live apply is a separate, explicitly-confirmed step.

k8s/environments/homelab.yaml

@@ -0,0 +1,25 @@
+# design.md §7b: cluster-specific values for the homelab environment.
+# No secrets here — Authentik client secret etc. flow through the existing
+# Vault/talos-cli pattern, referenced at deploy time, not inlined.
+namespace: sqs
+
+kafkaCluster:
+  nodePool:
+    replicas: 3
+    storage:
+      class: longhorn
+      sizeGi: 50
+    resources:
+      memory: 5Gi
+      cpu: "2"
+
+redis:
+  storageClass: longhorn
+  memoryLimit: 1Gi
+
+managementService:
+  ingress:
+    host: kmsvc.homelab.internal
+    clusterIssuer: homelab-ca
+  authentikIssuerURL: ""   # cluster/KMSVC_AUTHENTIK_ISSUER_URL — fill in once task 0 is done
+  authentikAudience: ""    # cluster/KMSVC_AUTHENTIK_AUDIENCE