feat: implement MACP phase 1 core protocol

tools/orchestrator-matrix/protocol/event.schema.json

@@ -22,8 +22,11 @@
         "task.assigned",
         "task.started",
         "task.progress",
+        "task.gated",
         "task.completed",
         "task.failed",
+        "task.escalated",
+        "task.retry.scheduled",
         "rail.check.started",
         "rail.check.passed",
         "rail.check.failed"
@@ -37,8 +40,10 @@
       "enum": [
         "pending",
         "running",
+        "gated",
         "completed",
-        "failed"
+        "failed",
+        "escalated"
       ]
     },
     "timestamp": {
@@ -50,7 +55,8 @@
       "enum": [
         "controller",
         "worker",
-        "quality-gate"
+        "quality-gate",
+        "dispatcher"
       ]
     },
     "message": {