feat: add cmdk dependency and enhance canvas node creation with edge splitting functionality

- Introduced the cmdk package for improved command palette capabilities.
- Enhanced the canvas placement context to support creating nodes with edge splitting, allowing for more dynamic node interactions.
- Updated the canvas inner component to utilize optimistic updates for node creation, improving user experience during interactions.
- Refactored node handling logic to incorporate new mutation types and streamline data management.

convex/storage.ts

@@ -1,5 +1,7 @@
-import { mutation } from "./_generated/server";
+import { mutation, query } from "./_generated/server";
+import { v } from "convex/values";
 import { requireAuth } from "./helpers";
+import type { Id } from "./_generated/dataModel";
 
 export const generateUploadUrl = mutation({
   args: {},
@@ -8,3 +10,41 @@ export const generateUploadUrl = mutation({
     return await ctx.storage.generateUploadUrl();
   },
 });
+
+/**
+ * Signierte URLs für alle Storage-Assets eines Canvas (gebündelt).
+ * `nodes.list` liefert keine URLs mehr, damit Node-Liste schnell bleibt.
+ */
+export const batchGetUrlsForCanvas = query({
+  args: { canvasId: v.id("canvases") },
+  handler: async (ctx, { canvasId }) => {
+    const user = await requireAuth(ctx);
+    const canvas = await ctx.db.get(canvasId);
+    if (!canvas || canvas.ownerId !== user.userId) {
+      throw new Error("Canvas not found");
+    }
+
+    const nodes = await ctx.db
+      .query("nodes")
+      .withIndex("by_canvas", (q) => q.eq("canvasId", canvasId))
+      .collect();
+
+    const ids = new Set<Id<"_storage">>();
+    for (const node of nodes) {
+      const data = node.data as Record<string, unknown> | undefined;
+      const sid = data?.storageId;
+      if (typeof sid === "string" && sid.length > 0) {
+        ids.add(sid as Id<"_storage">);
+      }
+    }
+
+    const entries = await Promise.all(
+      [...ids].map(
+        async (id) =>
+          [id, (await ctx.storage.getUrl(id)) ?? undefined] as const,
+      ),
+    );
+
+    return Object.fromEntries(entries) as Record<string, string | undefined>;
+  },
+});