feat(toolintent): record the session's active task as a session-local fact

Claiming a task now emits SessionWorkingTaskEvent{taskId, affectedPaths} into the
session's own stream (via a SessionFactRecorder port + event-store adapter), and
SessionContextProjection folds it into SessionContext.activeTask. So a gate learns
"which task is this session working, and its scope" by reading the session stream
— no cross-stream scan, no kernel->tasks dependency. Re-emitted on an affected_paths
edit by the claimant, so the snapshot scope stays current; latest wins on replay.

This is the data source the write-scope gate needs (next).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/server/src/main/kotlin/com/correx/apps/server/Main.kt

@@ -238,6 +238,7 @@ fun main() {
         taskDocumentResolver,
         taskArtifactResolver,
         taskSessionResolver,
+        com.correx.apps.server.tasks.EventStoreSessionFactRecorder(eventStore),
     )
     val toolRegistry = InfrastructureModule.createToolRegistry(
         buildToolConfig(

apps/server/src/main/kotlin/com/correx/apps/server/tasks/EventStoreSessionFactRecorder.kt

@@ -0,0 +1,36 @@
+package com.correx.apps.server.tasks
+
+import com.correx.core.events.events.EventMetadata
+import com.correx.core.events.events.NewEvent
+import com.correx.core.events.events.SessionWorkingTaskEvent
+import com.correx.core.events.stores.EventStore
+import com.correx.core.events.types.EventId
+import com.correx.core.events.types.SessionId
+import com.correx.core.events.types.TaskId
+import com.correx.infrastructure.tools.task.SessionFactRecorder
+import kotlinx.datetime.Clock
+import java.util.UUID
+
+/**
+ * Adapter for [SessionFactRecorder]: appends a [SessionWorkingTaskEvent] to the session's own stream
+ * when it claims (or re-scopes) a task, so [com.correx.core.toolintent.SessionContextProjection]
+ * folds it into the active task without scanning task streams.
+ */
+class EventStoreSessionFactRecorder(private val eventStore: EventStore) : SessionFactRecorder {
+
+    override suspend fun recordWorkingTask(sessionId: SessionId, taskId: TaskId, affectedPaths: List<String>) {
+        eventStore.append(
+            NewEvent(
+                metadata = EventMetadata(
+                    eventId = EventId(UUID.randomUUID().toString()),
+                    sessionId = sessionId,
+                    timestamp = Clock.System.now(),
+                    schemaVersion = 1,
+                    causationId = null,
+                    correlationId = null,
+                ),
+                payload = SessionWorkingTaskEvent(sessionId, taskId, affectedPaths),
+            ),
+        )
+    }
+}