Increase Prometheus and Loki data retention

Prometheus: 15d → 10y (3650d), PVC 20Gi → 200Gi
Loki: 31d (744h) → 365d (8760h), PVC 20Gi → 50Gi

Indri has 1.6 TB free on the minikube backing disk — the previous
15-day Prometheus retention was losing valuable long-term metrics data.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

argocd/manifests/loki/loki-config.yaml

@@ -40,7 +40,7 @@ storage_config:
     cache_location: /loki/tsdb-cache
 
 limits_config:
-  retention_period: 744h  # 31 days
+  retention_period: 8760h  # 365 days
 
 compactor:
   working_directory: /loki/compactor

argocd/manifests/loki/statefulset.yaml

@@ -63,4 +63,4 @@ spec:
         accessModes: ["ReadWriteOnce"]
         resources:
           requests:
-            storage: 20Gi
+            storage: 50Gi

argocd/manifests/prometheus/statefulset.yaml

@@ -24,7 +24,7 @@ spec:
           args:
             - --config.file=/etc/prometheus/prometheus.yml
             - --storage.tsdb.path=/prometheus
-            - --storage.tsdb.retention.time=15d
+            - --storage.tsdb.retention.time=3650d
             - --web.enable-remote-write-receiver
             - --web.enable-lifecycle
           ports:
@@ -65,4 +65,4 @@ spec:
         accessModes: ["ReadWriteOnce"]
         resources:
           requests:
-            storage: 20Gi
+            storage: 200Gi

docs/changelog.d/+increase-retention.infra.md

@@ -0,0 +1 @@
+Increase data retention: Prometheus 15d → 10y (200Gi), Loki 31d → 365d (50Gi)