feat: enhance file upload handling with improved file detection, size limits, and response formatting

src/db/files.ts

@@ -0,0 +1,26 @@
+import { eq } from 'drizzle-orm';
+import { db, files as fileSchema } from './index';
+import type { File } from './schema';
+
+export const findFileByHash = async (hash: string): Promise<File | null> => {
+  const result = await db.select().from(fileSchema).where(eq(fileSchema.fileHash, hash)).limit(1);
+  return result[0] || null;
+};
+
+export const findFileByPublicId = async (publicId: string): Promise<File | null> => {
+  const result = await db
+    .select()
+    .from(fileSchema)
+    .where(eq(fileSchema.publicId, publicId))
+    .limit(1);
+  return result[0] || null;
+};
+
+export const findFileByUniqueId = async (telegramFileUniqueId: string): Promise<File | null> => {
+  const result = await db
+    .select()
+    .from(fileSchema)
+    .where(eq(fileSchema.telegramFileUniqueId, telegramFileUniqueId))
+    .limit(1);
+  return result[0] || null;
+};