Extract more fields from JSON logs (zot compatibility)

Zot uses "message" instead of "msg" for the message field. Also extract
caller and repository from JSON logs for better filtering.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

argocd/manifests/alloy-k8s/configmap.yaml

@@ -90,11 +90,15 @@ data:
       }
 
       // Try to parse JSON logs (e.g., structured app logs)
+      // Handle both "msg" (common) and "message" (zot) field names
       stage.json {
         expressions = {
-          level   = "level",
-          message = "msg",
-          time    = "time",
+          level      = "level",
+          msg        = "msg",
+          message    = "message",
+          time       = "time",
+          caller     = "caller",
+          repository = "repository",
         }
       }
 
@@ -111,9 +115,10 @@ data:
       // Extract labels from parsed data (works for both JSON and logfmt)
       stage.labels {
         values = {
-          level     = "",
-          caller    = "",
-          component = "",
+          level      = "",
+          caller     = "",
+          component  = "",
+          repository = "",
         }
       }
     }