Add versioned task context capsules

schemas/result.schema.json

@@ -32,6 +32,7 @@
             "mcp.dependencies",
             "mcp.impact",
             "mcp.context",
+            "mcp.task_context",
             "mcp.validate_project",
             "mcp.render_status",
             "mcp.visualize",
@@ -149,6 +150,7 @@
         "kind": {
           "enum": [
             "context.items",
+            "task-context.items",
             "changeset.list",
             "changeset.inspect",
             "changeset.validate",