feat: prepare six-lesson trial backend with reliable rewards and operations

Co-authored-by: Cursor <cursoragent@cursor.com>

test/production-error.test.ts

@@ -0,0 +1,46 @@
+import 'reflect-metadata'
+import assert from 'node:assert/strict'
+import { HttpException, HttpStatus } from '@nestjs/common'
+import { ApiExceptionFilter } from '../src/common/filters/api-exception.filter'
+
+const filter = new ApiExceptionFilter()
+
+function runFilter(exception: unknown): { status: number; body: { error: string } } {
+  let status = 0
+  let body: { error: string } = { error: '' }
+  const host = {
+    switchToHttp: () => ({
+      getResponse: () => ({
+        status(code: number) {
+          status = code
+          return {
+            send(payload: { error: string }) {
+              body = payload
+            },
+          }
+        },
+      }),
+    }),
+  }
+  filter.catch(exception, host as never)
+  return { status, body }
+}
+
+const prev = process.env.NODE_ENV
+process.env.NODE_ENV = 'production'
+
+const internal = runFilter(
+  new Error('SqliteError: constraint at /secret/path/app.db\n    at foo.ts:1:1'),
+)
+assert.equal(internal.status, HttpStatus.INTERNAL_SERVER_ERROR)
+assert.equal(internal.body.error, 'خطای سرور')
+assert.ok(!JSON.stringify(internal.body).includes('app.db'))
+
+const httpErr = runFilter(
+  new HttpException('SQLITE_BUSY: database is locked', HttpStatus.BAD_REQUEST),
+)
+assert.equal(httpErr.body.error, 'درخواست نامعتبر است')
+
+process.env.NODE_ENV = prev
+
+console.log('production-error tests passed')