upgrade logging loki and alloy

logging/docker-compose.yaml

@@ -2,10 +2,9 @@ version: '3.8'
 
 services:
   loki:
-    # Pinned, not :latest — this host's kernel (5.16.7, Fedora 35 from 2022) resets
-    # every TCP connection to containers built with newer Go toolchains
-    # (confirmed: grafana/loki:latest, built with go1.26.4, fails; 2.9.8 works).
-    image: grafana/loki:2.9.8
+    # Keep a fixed release for reproducible Portainer redeploys. The 2.9.8 ->
+    # 3.7.2 upgrade was validated against a copy of this stack's TSDB v13 data.
+    image: grafana/loki:3.7.2
     container_name: loki
     command: -config.file=/etc/loki/config.yaml
     restart: unless-stopped
@@ -16,10 +15,9 @@ services:
       - logging-nw
 
   alloy:
-    # Pinned for the same reason as loki — see comment there. v1.5.0
-    # specifically (not v1.4.3) because it's the first release with
-    # syslog_format = "rfc3164" support, needed below.
-    image: grafana/alloy:v1.5.0
+    # Keep a fixed release for reproducible Portainer redeploys. The current
+    # RFC3164 config and an end-to-end Alloy -> Loki probe passed on v1.16.1.
+    image: grafana/alloy:v1.16.1
     container_name: alloy
     command:
       - run