harden database interactions and improve error handling

server/api/courses/[id]/index.get.ts

@@ -1,5 +1,5 @@
 import { db } from "../../../db/index";
-import { courses, topics, userProgress, lessons } from "../../../db/schema";
+import { courses, topics, lessons } from "../../../db/schema";
 import { eq, inArray } from "drizzle-orm";
 
 export default defineEventHandler(async (event) => {
@@ -16,13 +16,6 @@ export default defineEventHandler(async (event) => {
     orderBy: (t, { asc }) => asc(t.order),
   });
 
-  const progressRows = await db.query.userProgress.findMany({
-    where: eq(userProgress.courseId, id),
-  });
-
-  const progressMap: Record<string, typeof progressRows[0]> = {};
-  for (const p of progressRows) progressMap[p.topicId] = p;
-
   const topicIds = topicRows.map((t) => t.id);
 
   const lessonRows = topicIds.length
@@ -37,7 +30,6 @@ export default defineEventHandler(async (event) => {
     topics: topicRows.map((t) => ({
       ...t,
       prerequisiteTopicIds: JSON.parse(t.prerequisiteTopicIds ?? "[]"),
-      progress: progressMap[t.id] ?? null,
       hasLesson: !!lessonMap[t.id],
       lessonCost: lessonMap[t.id]?.costTotal ?? null,
     })),