P6.2: Fix peer discovery DNS SRV service name and add POD_IP

Fixes the peer discovery service name mismatch that caused SRV lookups
to fail. The headless Service is named "<fullname>-headless" but the
config was using ".Release.Name-headless", which didn't match.

Also adds POD_IP to the Downward API env vars (was missing).

Changes:
- _helpers.tpl: Use miroir.fullname instead of Release.Name for service_name default
- values.yaml: Document service_name default as auto-derived
- miroir-deployment.yaml: Add POD_IP env var via Downward API
- verify_p6_2_peer_discovery.sh: Add POD_IP verification step

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

charts/miroir/templates/_helpers.tpl

@@ -178,7 +178,7 @@ resharding:
   retain_old_index_hours: {{ .Values.miroir.resharding.retain_old_index_hours | default 48 }}
   allowed_windows: {{ .Values.miroir.resharding.allowed_windows | default list | toJson }}
 peer_discovery:
-  service_name: {{ .Values.miroir.peer_discovery.service_name | default .Release.Name }}-headless
+  service_name: {{ .Values.miroir.peer_discovery.service_name | default (printf "%s-headless" (include "miroir.fullname" .)) }}
   refresh_interval_s: {{ .Values.miroir.peer_discovery.refresh_interval_s | default 15 }}
 leader_election:
   enabled: {{ .Values.miroir.leader_election.enabled | default true }}

charts/miroir/templates/miroir-deployment.yaml

@@ -67,6 +67,10 @@ spec:
               valueFrom:
                 fieldRef:
                   fieldPath: metadata.namespace
+            - name: POD_IP
+              valueFrom:
+                fieldRef:
+                  fieldPath: status.podIP
             - name: MIROIR_CONFIG_PATH
               value: /config/miroir.yaml
             - name: MIROIR_MASTER_KEY

charts/miroir/values.yaml

@@ -112,7 +112,7 @@ miroir:
     retain_old_index_hours: 48
     allowed_windows: []                # e.g., ["22:00-04:00 UTC"]
   peer_discovery:
-    service_name: miroir-headless
+    service_name: ""  # default: "<fullname>-headless" (auto-derived from release name)
     refresh_interval_s: 15
   leader_election:
     enabled: true                      # auto-true when replicas > 1

tests/verify_p6_2_peer_discovery.sh

@@ -62,7 +62,16 @@ else
 fi
 
 echo ""
-echo "6. Checking peer_discovery configuration..."
+echo "6. Verifying POD_IP env var is set (if running in K8s)..."
+POD_IP="${POD_IP:-unknown}"
+if [ "$POD_IP" != "unknown" ]; then
+    echo "   ✓ POD_IP=$POD_IP"
+else
+    echo "   ⚠ POD_IP not set (not running in Kubernetes)"
+fi
+
+echo ""
+echo "7. Checking peer_discovery configuration..."
 # The peer_discovery config is internal, but we can check the log for the refresh loop starting
 # For local dev, peer discovery may be disabled if POD_NAME=unknown
 if [ "$POD_NAME" = "unknown" ]; then