fix(convex): rename helper modules to valid convex paths

tests/convex/ai-utils.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { assertNodeBelongsToCanvasOrThrow } from "@/convex/ai-utils";
+import { assertNodeBelongsToCanvasOrThrow } from "@/convex/ai_utils";
 
 describe("assertNodeBelongsToCanvasOrThrow", () => {
   it("accepts matching node/canvas relation", () => {

tests/convex/batch-validation-utils.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from "vitest";
 import type { Id } from "@/convex/_generated/dataModel";
-import { validateBatchNodesForUserOrThrow } from "@/convex/batch-validation-utils";
+import { validateBatchNodesForUserOrThrow } from "@/convex/batch_validation_utils";
 
 describe("validateBatchNodesForUserOrThrow", () => {
   it("rejects mixed canvas ids in one batch", async () => {

tests/convex/polar-utils.test.ts

@@ -5,7 +5,7 @@ import {
   buildTopUpPaidIdempotencyKey,
   registerWebhookEventOnce,
   type WebhookEventRepo,
-} from "@/convex/polar-utils";
+} from "@/convex/polar_utils";
 
 describe("polar idempotency helpers", () => {
   it("builds stable idempotency keys", () => {