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/charts/kafka-cluster/templates/kafka-cluster.yaml

@@ -0,0 +1,30 @@
+apiVersion: kafka.strimzi.io/v1beta2
+kind: Kafka
+metadata:
+  name: {{ .Values.clusterName }}
+  namespace: {{ .Values.namespace }}
+  annotations:
+    strimzi.io/node-pools: enabled
+    strimzi.io/kraft: enabled
+spec:
+  kafka:
+    version: 4.0.0
+    metadataVersion: 4.0-IV3
+    listeners:
+      - name: plain
+        port: 9092
+        type: internal
+        tls: false
+      - name: tls
+        port: 9093
+        type: internal
+        tls: true
+    config:
+      default.replication.factor: {{ .Values.kafka.replicationFactor }}
+      min.insync.replicas: {{ .Values.kafka.minInsyncReplicas }}
+      offsets.topic.replication.factor: {{ .Values.kafka.replicationFactor }}
+      transaction.state.log.replication.factor: {{ .Values.kafka.replicationFactor }}
+      transaction.state.log.min.isr: {{ .Values.kafka.minInsyncReplicas }}
+  entityOperator:
+    topicOperator: {}
+    userOperator: {}

k8s/charts/kafka-cluster/templates/kafka-nodepool.yaml

@@ -0,0 +1,39 @@
+apiVersion: kafka.strimzi.io/v1beta2
+kind: KafkaNodePool
+metadata:
+  name: {{ .Values.clusterName }}-pool
+  namespace: {{ .Values.namespace }}
+  labels:
+    strimzi.io/cluster: {{ .Values.clusterName }}
+spec:
+  replicas: {{ .Values.nodePool.replicas }}
+  roles:
+    - controller
+    - broker
+  storage:
+    type: persistent-claim
+    size: {{ .Values.nodePool.storage.sizeGi }}Gi
+    class: {{ .Values.nodePool.storage.class }}
+    deleteClaim: false
+  resources:
+    limits:
+      memory: {{ .Values.nodePool.resources.memory }}
+      cpu: {{ .Values.nodePool.resources.cpu | quote }}
+    requests:
+      memory: {{ .Values.nodePool.resources.memory }}
+      cpu: {{ .Values.nodePool.resources.cpu | quote }}
+  template:
+    pod:
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+            - weight: 100
+              podAffinityTerm:
+                topologyKey: {{ .Values.nodePool.antiAffinityTopologyKey }}
+                labelSelector:
+                  matchLabels:
+                    strimzi.io/cluster: {{ .Values.clusterName }}
+    kafkaContainer:
+      env:
+        - name: KAFKA_HEAP_OPTS
+          value: {{ .Values.nodePool.heapOpts | quote }}