feat(canvas): 自由画布 - 增强空白起点、外观设置与节点连接体验 (#356)

web/src/lib/canvas/canvas-starter.ts

@@ -0,0 +1,20 @@
+export type CanvasStarterMode = "guided" | "freeform";
+
+export type CanvasEmptyStateKind = "none" | "guided" | "freeform" | "linked";
+
+export function resolveCanvasEmptyStateKind({
+    nodeCount,
+    shortDramaEnabled,
+    isProjectLinked,
+    starterMode,
+}: {
+    nodeCount: number;
+    shortDramaEnabled: boolean;
+    isProjectLinked: boolean;
+    starterMode?: CanvasStarterMode;
+}): CanvasEmptyStateKind {
+    if (nodeCount > 0) return "none";
+    if (!shortDramaEnabled) return "freeform";
+    if (isProjectLinked) return "linked";
+    return starterMode === "freeform" ? "freeform" : "guided";
+}