feat(metrics): add notification-metrics module + emit send outcomes (…

build.sbt

@@ -76,6 +76,15 @@ lazy val common = project.in(file("common"))
   )
   .enablePlugins(AkkaGrpcPlugin)
 
+// Story 13.9 — dependency-light metrics module (only the Prometheus client). Kept separate from
+// common so downstream consumers can depend on notification metrics without the full common stack.
+lazy val metrics = project.in(file("metrics"))
+  .configs(IntegrationTest)
+  .settings(
+    Defaults.itSettings,
+    moduleSettings
+  )
+
 lazy val core = project.in(file("core"))
   .configs(IntegrationTest)
   .settings(
@@ -85,7 +94,8 @@ lazy val core = project.in(file("core"))
   )
   .enablePlugins(BuildInfoPlugin)
   .dependsOn(
-    common % "compile->compile;test->test;it->it"
+    common % "compile->compile;test->test;it->it",
+    metrics
   )
 
 lazy val testkit = project.in(file("testkit"))
@@ -111,7 +121,7 @@ lazy val api = project.in(file("api"))
   )
 
 lazy val root = project.in(file("."))
-  .aggregate(common, core, testkit, api)
+  .aggregate(common, metrics, core, testkit, api)
   .configs(IntegrationTest)
   .settings(
     Defaults.itSettings,

core/src/main/scala/app/softnetwork/notification/persistence/typed/NotificationBehavior.scala

@@ -18,6 +18,7 @@ import app.softnetwork.persistence.typed._
 import app.softnetwork.notification.message._
 import app.softnetwork.notification.model._
 import app.softnetwork.notification.spi.NotificationProvider
+import app.softnetwork.notification.metrics.NotificationMetrics
 import app.softnetwork.scheduler.config.SchedulerSettings
 import app.softnetwork.notification.model.NotificationStatus._
 
@@ -514,8 +515,13 @@ trait NotificationBehavior[T <: Notification]
           updatedNotification.status match {
             case Sent | Delivered =>
               audit.event(cid, "notification_sent", "channel" -> channel)
+              // Story 13.9 — terminal-send metric. `template` is empty here: this layer has no
+              // bounded template identifier (see the note above) and a raw subject would explode
+              // the series cardinality; the producer owns template attribution on the enqueue side.
+              NotificationMetrics.notification(channel, "", "sent")
             case Undelivered | Rejected =>
               audit.event(cid, "notification_failed", "channel" -> channel)
+              NotificationMetrics.notification(channel, "", "failed")
             case _ => // still pending — no terminal audit line yet
           }
         }

metrics/build.sbt

@@ -0,0 +1,10 @@
+organization := "app.softnetwork.notification"
+
+name := "notification-metrics"
+
+libraryDependencies ++= Seq(
+  // Lean, dependency-light module (Story 13.9): only the Prometheus client, so consumers
+  // (e.g. softclient4es-license-server) can depend on notification metrics WITHOUT pulling the
+  // full notification-common stack (firebase-admin, pushy, commons-email, ...).
+  "io.prometheus" % "prometheus-metrics-core" % Versions.prometheus
+)

metrics/src/main/scala/app/softnetwork/notification/metrics/NotificationMetrics.scala

@@ -0,0 +1,42 @@
+package app.softnetwork.notification.metrics
+
+import io.prometheus.metrics.core.metrics.Counter
+
+/** Notification delivery metrics.
+  *
+  * Lives in its own dependency-light `notification-metrics` module (Story 13.9) so consumers can
+  * depend on it without pulling the full `notification-common` stack.
+  *
+  * Registers into the global
+  * [[io.prometheus.metrics.model.registry.PrometheusRegistry#defaultRegistry]], so any process that
+  * exposes that registry on a `/metrics` route (e.g. the softclient4es license-server, Story 13.6)
+  * scrapes these series automatically — no wiring is required here.
+  *
+  * The counter name is declared WITHOUT the `_total` suffix — the Prometheus client appends it at
+  * exposition, so the exposed series is `notification_total`.
+  *
+  * Labels:
+  *   - `service` — always `"notification"`.
+  *   - `channel` — the `NotificationType` name (e.g. `MAIL_TYPE`, `SMS_TYPE`), matching the Story
+  *     13.7 audit `channel` field.
+  *   - `template` — a BOUNDED template identifier, or empty when none is available at the call
+  *     site. Never pass an unbounded free-text value (e.g. a raw subject): it would explode the
+  *     series cardinality. The terminal send path (NotificationBehavior) has no template identifier
+  *     and passes an empty value; the producer that enqueues the notification owns template
+  *     attribution.
+  *   - `outcome` — one of `enqueued` | `sent` | `failed` | `retried`.
+  */
+object NotificationMetrics {
+
+  private val Service = "notification"
+
+  private val notifications: Counter = Counter
+    .builder()
+    .name("notification")
+    .help("Notifications, by channel / template / outcome")
+    .labelNames("service", "channel", "template", "outcome")
+    .register()
+
+  def notification(channel: String, template: String, outcome: String): Unit =
+    notifications.labelValues(Service, channel, template, outcome).inc()
+}

project/Versions.scala

@@ -11,4 +11,6 @@ object Versions {
   val scheduler = "0.8-SNAPSHOT"
 
   val scalatest = "3.2.16"
+
+  val prometheus = "1.7.0"
 }