feat: make demo story screen interactive

src/app/turnAdapter.ts

@@ -0,0 +1,93 @@
+import type { PlayerView, PresentationBeat, TurnRequest, TurnResult } from "@contracts";
+
+const DEMO_LATENCY_MS = 120;
+
+function nextNodeId(currentNodeId: string): string {
+  const match = currentNodeId.match(/^(.*?)(\d+)$/);
+  if (!match) return `${currentNodeId}_next`;
+
+  const [, prefix, digits] = match;
+  return `${prefix}${String(Number(digits) + 1).padStart(digits.length, "0")}`;
+}
+
+function replyBeats(request: TurnRequest): PresentationBeat[] {
+  if (request.intent === "continue") {
+    return [
+      {
+        id: `${request.actionId}_rain`,
+        kind: "narration",
+        speaker: null,
+        text: "一阵风越过站台，雨点敲在铁棚上，短暂盖过了远处的水声。",
+        visual: null
+      },
+      {
+        id: `${request.actionId}_nana`,
+        kind: "dialogue",
+        speaker: "娜娜",
+        text: "如果你还没想好，就先听一会儿雨吧。",
+        visual: {
+          character: "nana",
+          expression: "guarded",
+          pose: null,
+          scene: null
+        }
+      }
+    ];
+  }
+
+  return [
+    {
+      id: `${request.actionId}_player`,
+      kind: "action",
+      speaker: "你",
+      // The demo repeats only the player's literal input. It never invents player speech or intent.
+      text: request.input,
+      visual: null
+    },
+    {
+      id: `${request.actionId}_nana`,
+      kind: "dialogue",
+      speaker: "娜娜",
+      text: "娜娜静静听完，攥着外套的手稍微松开了一些。“我知道了。”",
+      visual: {
+        character: "nana",
+        expression: "uneasy",
+        pose: "holding_coat",
+        scene: null
+      }
+    }
+  ];
+}
+
+/**
+ * Browser-only M0 adapter. It deliberately mirrors the future runtime boundary:
+ * App -> TurnRequest -> TurnResult. No Tauri command or persisted branch is implied.
+ */
+export async function submitDemoTurn(
+  request: TurnRequest,
+  currentView: PlayerView
+): Promise<TurnResult> {
+  await new Promise((resolve) => window.setTimeout(resolve, DEMO_LATENCY_MS));
+
+  const committedNodeId = nextNodeId(currentView.nodeId);
+  const previousHistory = currentView.history.map((node) => ({ ...node, isCurrent: false }));
+
+  return {
+    committedNodeId,
+    playerView: {
+      ...currentView,
+      nodeId: committedNodeId,
+      beats: [...currentView.beats, ...replyBeats(request)].slice(-8),
+      history: [
+        ...previousHistory,
+        {
+          id: committedNodeId,
+          parentId: currentView.nodeId,
+          branchId: currentView.branchId,
+          label: request.intent === "continue" ? "雨声中的停顿" : "回应娜娜",
+          isCurrent: true
+        }
+      ]
+    }
+  };
+}