refactor flows into canonical runtime architecture

core/flow-kernel/step-registry.js

@@ -0,0 +1,53 @@
+(function attachBackgroundStepRegistry(root, factory) {
+  root.MultiPageBackgroundStepRegistry = factory();
+})(typeof self !== 'undefined' ? self : globalThis, function createBackgroundStepRegistryModule() {
+  function createNodeRegistry(definitions = []) {
+    const ordered = (Array.isArray(definitions) ? definitions : [])
+      .map((definition) => ({
+        flowId: String(definition?.flowId || '').trim(),
+        nodeId: String(definition?.nodeId || definition?.key || '').trim(),
+        displayOrder: Number(definition?.displayOrder ?? definition?.order ?? definition?.id),
+        executeKey: String(definition?.executeKey || definition?.key || definition?.nodeId || '').trim(),
+        title: String(definition?.title || '').trim(),
+        execute: definition?.execute,
+      }))
+      .filter((definition) => definition.nodeId)
+      .sort((left, right) => {
+        const leftOrder = Number.isFinite(left.displayOrder) ? left.displayOrder : 0;
+        const rightOrder = Number.isFinite(right.displayOrder) ? right.displayOrder : 0;
+        if (leftOrder !== rightOrder) return leftOrder - rightOrder;
+        return left.nodeId.localeCompare(right.nodeId);
+      });
+
+    const byId = new Map(ordered.map((definition) => [definition.nodeId, definition]));
+
+    function getNodeDefinition(nodeId) {
+      return byId.get(String(nodeId || '').trim()) || null;
+    }
+
+    function getOrderedNodes() {
+      return ordered.slice();
+    }
+
+    function executeNode(nodeId, state) {
+      const definition = getNodeDefinition(nodeId);
+      if (!definition) {
+        throw new Error(`Unknown node: ${nodeId}`);
+      }
+      if (typeof definition.execute !== 'function') {
+        throw new Error(`Missing node executor: ${definition.executeKey || definition.nodeId}`);
+      }
+      return definition.execute(state);
+    }
+
+    return {
+      executeNode,
+      getNodeDefinition,
+      getOrderedNodes,
+    };
+  }
+
+  return {
+    createNodeRegistry,
+  };
+});