feat(transitions): tasks_ready predicate for execution loop

New TasksReady condition driven by EvaluationContext.readyTaskCount,
fed at resolve time via a kernel-declared ReadyTaskCounter interface
implemented in apps/server over TaskService (keeps core:kernel
decoupled from core:tasks). Loops a graph while ready>0, exits at 0.

testing/transitions/src/test/kotlin/DefaultTransitionResolverTest.kt

@@ -1,5 +1,7 @@
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
+import com.correx.core.transitions.conditions.Not
+import com.correx.core.transitions.conditions.TasksReady
 import com.correx.core.events.types.TransitionId
 import com.correx.core.transitions.evaluation.EvaluationContext
 import com.correx.core.transitions.evaluation.TransitionConditionEvaluator
@@ -210,6 +212,28 @@ class DefaultTransitionResolverTest {
         )
     }
 
+    @Test
+    fun `TasksReady loops while ready tasks remain and exits at zero`() {
+        val graph = graph(
+            start = "claim",
+            transitions = setOf(
+                edge(id = "loop", from = "claim", to = "claim", condition = TasksReady),
+                edge(id = "exit", from = "claim", to = "done", condition = Not(TasksReady)),
+            ),
+            stages = setOf("claim", "done"),
+        )
+        val base = context(currentStage = "claim")
+
+        assertEquals(
+            StageId("claim"),
+            (resolver.resolve(graph, base.copy(readyTaskCount = 2)) as TransitionDecision.Move).to,
+        )
+        assertEquals(
+            StageId("done"),
+            (resolver.resolve(graph, base.copy(readyTaskCount = 0)) as TransitionDecision.Move).to,
+        )
+    }
+
     private fun alwaysTrue() =
         TransitionCondition { true }