feat: forward the agones and matchmaking blocks to forge

plugin/src/main/kotlin/gg/grounds/push/manifest/GroundsYaml.kt

@@ -36,6 +36,17 @@ data class GroundsYaml(
      * Architecture).
      */
     val services: Map<String, ServiceDecl>? = null,
+    /**
+     * Agones knobs. Only meaningful for the types forge renders as a Fleet.
+     */
+    val agones: Agones? = null,
+    /**
+     * Hands the GameServer's lifecycle to the matchmaker. Its mere presence makes forge render
+     * `GROUNDS_MATCHMAKING` onto the pod and declare the Agones `matches` counter with this
+     * capacity — and without the counter DECLARED, the matchmaker's allocation selector matches
+     * nothing and no match can ever be placed on the fleet.
+     */
+    val matchmaking: Matchmaking? = null,
 ) {
     data class Resources(val cpu: String? = null, val memory: String? = null)
 
@@ -68,6 +79,10 @@ data class GroundsYaml(
     }
 }
 
+data class Agones(val replicas: Int? = null)
+
+data class Matchmaking(val matchesPerServer: Int)
+
 class GroundsYamlParseException(
     message: String,
     cause: Throwable? = null,
@@ -114,11 +129,14 @@ object GroundsYamlParser {
         val resources = raw.optResources("resources")
         val events = raw.optEvents("events")
         val services = raw.optServices("services")
+        val agones = raw.optAgones("agones")
+        val matchmaking = raw.optMatchmaking("matchmaking")
         return GroundsYaml(
             name = name, type = type, baseImage = baseImage,
             jar = jar, plugins = plugins,
             target = target, resources = resources, flavors = flavors,
             events = events, services = services,
+            agones = agones, matchmaking = matchmaking,
         )
     }
 
@@ -145,6 +163,38 @@ object GroundsYamlParser {
         return v.ifEmpty { null }
     }
 
+    private fun Map<*, *>.optAgones(key: String): Agones? {
+        val v = this[key] ?: return null
+        if (v !is Map<*, *>) throw GroundsYamlParseException(
+            "grounds.yaml: '$key' must be a mapping, got ${v.javaClass.simpleName}",
+        )
+        val replicas = v["replicas"]
+        return Agones(
+            replicas = when (replicas) {
+                null -> null
+                is Int -> replicas
+                else -> throw GroundsYamlParseException(
+                    "grounds.yaml: 'agones.replicas' must be an integer",
+                )
+            },
+        )
+    }
+
+    private fun Map<*, *>.optMatchmaking(key: String): Matchmaking? {
+        val v = this[key] ?: return null
+        if (v !is Map<*, *>) throw GroundsYamlParseException(
+            "grounds.yaml: '$key' must be a mapping, got ${v.javaClass.simpleName}",
+        )
+        val perServer = v["matchesPerServer"]
+            ?: throw GroundsYamlParseException(
+                "grounds.yaml: 'matchmaking.matchesPerServer' is required",
+            )
+        if (perServer !is Int) throw GroundsYamlParseException(
+            "grounds.yaml: 'matchmaking.matchesPerServer' must be an integer",
+        )
+        return Matchmaking(matchesPerServer = perServer)
+    }
+
     private fun Map<*, *>.optResources(
         key: String,
         label: String = key,

plugin/src/main/kotlin/gg/grounds/push/tasks/GroundsPushTask.kt

@@ -535,6 +535,20 @@ abstract class GroundsPushTask : DefaultTask() {
         pluginSources: List<SourceRef>,
     ): String = Json.encodeToString(JsonObject.serializer(), buildJsonObject {
         put("name", JsonPrimitive(manifest.name))
+        // Fleet knobs. Hand-built JSON means a block that is not named here simply
+        // does not exist as far as forge is concerned — `matchmaking:` was dropped
+        // in silence, so the fleet came up with no `matches` counter and no
+        // GROUNDS_MATCHMAKING, and the matchmaker could never place a match on it.
+        manifest.agones?.let { agones ->
+            put("agones", buildJsonObject {
+                agones.replicas?.let { put("replicas", JsonPrimitive(it)) }
+            })
+        }
+        manifest.matchmaking?.let { mm ->
+            put("matchmaking", buildJsonObject {
+                put("matchesPerServer", JsonPrimitive(mm.matchesPerServer))
+            })
+        }
         // Forge maps these to the gg.grounds/events SA annotation + NATS_URL.
         manifest.events?.takeIf { it.isNotEmpty() }?.let { events ->
             put("events", buildJsonArray {