Refactor pipeline and assistant page components for improved structure and performance

- Remove unused imports and classes from pipeline.py to streamline the codebase.
- Consolidate dynamic variable handling and workflow management in AssistantPage, enhancing clarity and maintainability.
- Update WorkflowEditor to utilize a more modular approach, improving the overall architecture and reducing complexity.
- Enhance the import structure across components for better organization and readability.

frontend/src/components/assistant-editor/use-workflow-editor-state.ts

@@ -0,0 +1,73 @@
+"use client";
+
+import { useState } from "react";
+
+import type { WorkflowSettings } from "@/components/workflow/types";
+import { defaultGraph, type WorkflowGraph } from "@/components/workflow/specs";
+import type { DynamicVariableDefinition } from "@/lib/api";
+import { defaultTurnConfig } from "@/lib/turn-config";
+
+function initialWorkflowSettings(): WorkflowSettings {
+  const graph = defaultGraph();
+  return {
+    globalPrompt: graph.settings.globalPrompt,
+    llm: graph.settings.defaultLlmResourceId,
+    asr: graph.settings.defaultAsrResourceId,
+    tts: graph.settings.defaultTtsResourceId,
+    toolIds: graph.settings.toolIds,
+    knowledgeBaseId: graph.settings.knowledgeBaseId,
+    knowledgeRetrievalConfig: {
+      mode: graph.settings.knowledgeMode,
+      topN: graph.settings.knowledgeTopN,
+      scoreThreshold: graph.settings.knowledgeScoreThreshold,
+    },
+    allowInterrupt: true,
+    turnConfig: defaultTurnConfig(),
+  };
+}
+
+/** Owns Workflow editor state; AssistantPage only coordinates loading and saving. */
+export function useWorkflowEditorState() {
+  const [workflowName, setWorkflowName] = useState("");
+  const [workflowGraph, setWorkflowGraph] = useState<WorkflowGraph>(() =>
+    defaultGraph(),
+  );
+  const [workflowSettings, setWorkflowSettings] = useState<WorkflowSettings>(
+    initialWorkflowSettings,
+  );
+  const [workflowDynamicVariableDefinitions, setWorkflowDynamicVariableDefinitions] =
+    useState<Record<string, DynamicVariableDefinition>>({});
+  const [workflowDebugOpen, setWorkflowDebugOpen] = useState(false);
+  const [workflowSettingsOpen, setWorkflowSettingsOpen] = useState(false);
+  const [workflowEditingNodeId, setWorkflowEditingNodeId] = useState<string | null>(
+    null,
+  );
+  const [workflowEditingEdgeId, setWorkflowEditingEdgeId] = useState<string | null>(
+    null,
+  );
+  const [activeNodeId, setActiveNodeId] = useState<string | null>(null);
+  const [dynamicVariablesOpen, setDynamicVariablesOpen] = useState(false);
+
+  return {
+    workflowName,
+    setWorkflowName,
+    workflowGraph,
+    setWorkflowGraph,
+    workflowSettings,
+    setWorkflowSettings,
+    workflowDynamicVariableDefinitions,
+    setWorkflowDynamicVariableDefinitions,
+    workflowDebugOpen,
+    setWorkflowDebugOpen,
+    workflowSettingsOpen,
+    setWorkflowSettingsOpen,
+    workflowEditingNodeId,
+    setWorkflowEditingNodeId,
+    workflowEditingEdgeId,
+    setWorkflowEditingEdgeId,
+    activeNodeId,
+    setActiveNodeId,
+    dynamicVariablesOpen,
+    setDynamicVariablesOpen,
+  };
+}