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.

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/DefaultSessionOrchestrator.kt

@@ -61,7 +61,8 @@ class DefaultSessionOrchestrator(
     private val compactionService: JournalCompactionService? = null,
     artifactKindRegistry: ArtifactKindRegistry? = null,
     repoKnowledgeRetriever: RepoKnowledgeRetriever? = null,
-) : SessionOrchestrator(repositories, engines, artifactStore, decisionJournalRepository, artifactKindRegistry = artifactKindRegistry, repoKnowledgeRetriever = repoKnowledgeRetriever), ApprovalGateway {
+    readyTaskCounter: ReadyTaskCounter? = null,
+) : SessionOrchestrator(repositories, engines, artifactStore, decisionJournalRepository, artifactKindRegistry = artifactKindRegistry, repoKnowledgeRetriever = repoKnowledgeRetriever, readyTaskCounter = readyTaskCounter), ApprovalGateway {
     override val tokenizer: Tokenizer? = tokenizer
     override val cancellations: ConcurrentHashMap<SessionId, AtomicBoolean> =
         ConcurrentHashMap<SessionId, AtomicBoolean>()

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/ReadyTaskCounter.kt

@@ -0,0 +1,13 @@
+package com.correx.core.kernel.orchestration
+
+import com.correx.core.events.types.SessionId
+
+/**
+ * How many tasks are ready to claim for a session's project, read at transition-resolution time
+ * (invariant #9: the observation is taken when the predicate runs). Implemented in apps/server over
+ * the task projection — core:kernel stays decoupled from core:tasks. Null injection ⇒ count 0, so
+ * the [com.correx.core.transitions.conditions.TasksReady] predicate is simply false.
+ */
+fun interface ReadyTaskCounter {
+    fun count(sessionId: SessionId): Int
+}

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/SessionOrchestrator.kt

@@ -187,6 +187,7 @@ abstract class SessionOrchestrator(
     private val decisionJournalRenderer: DecisionJournalRenderer = DecisionJournalRenderer(),
     private val artifactKindRegistry: ArtifactKindRegistry? = null,
     private val repoKnowledgeRetriever: RepoKnowledgeRetriever? = null,
+    private val readyTaskCounter: ReadyTaskCounter? = null,
 ) {
     private val log = LoggerFactory.getLogger(this::class.java)
     private val eventStore: EventStore = repositories.eventStore
@@ -1856,6 +1857,7 @@ abstract class SessionOrchestrator(
             currentStage = currentStageId,
             artifacts = artifacts,
             artifactContent = artifactContent,
+            readyTaskCount = readyTaskCounter?.count(sessionId) ?: 0,
         )
         return transitionResolver.resolve(graph, ctx)
     }