refactor: migrate routes to v2 flat routes convention

- Rename all route files from folder-based to dot-based naming
- Rename index.tsx to _index.tsx for index routes
- Update relative imports to match new file structure
- Update test import from ~/routes to ~/routes/_index
- Add serverModuleFormat: 'cjs' to fix @heroicons/react ESM issue

Route examples:
- routes/index.tsx → routes/_index.tsx
- routes/dashboard/course.tsx → routes/dashboard.course.tsx
- routes/dashboard/course/$lessonId.tsx → routes/dashboard.course.$lessonId.tsx

Author: zainfathoni

app/components/sections/__tests__/index.test.tsx

@@ -1,5 +1,5 @@
 import { render } from '#test/test-utils'
-import HomePage from '~/routes'
+import HomePage from '~/routes/_index'
 
 describe('Home Page', () => {
   it('renders the Home Page without error', () => {

app/routes/index.tsx app/routes/_index.tsxapp/routes/index.tsx renamed to app/routes/_index.tsx

@@ -2,12 +2,7 @@ import { Dialog, Transition } from '@headlessui/react'
 import { Fragment } from 'react'
 import type { ActionFunction, LoaderFunction } from '@remix-run/node'
 import { json, redirect } from '@remix-run/node'
-import {
-  Form,
-  useLoaderData,
-  useMatches,
-  useNavigate,
-} from '@remix-run/react'
+import { Form, useLoaderData, useMatches, useNavigate } from '@remix-run/react'
 import { Lesson } from '@prisma/client'
 import { Field } from '~/components/form-elements'
 import { classNames } from '~/utils/class-names'

app/routes/dashboard/index.tsx app/routes/dashboard._index.tsxapp/routes/dashboard/index.tsx renamed to app/routes/dashboard._index.tsx

@@ -8,7 +8,7 @@ import {
   ExternalLinkIcon,
 } from '@heroicons/react/solid'
 import { PaperClipIcon } from '@heroicons/react/outline'
-import { CourseContextType } from '../course'
+import { CourseContextType } from './dashboard.course'
 import { getFirstCourse } from '~/models/course'
 import { getLessonById, LessonWithAttachments } from '~/models/lesson'
 import { requireUpdatedUser } from '~/services/auth.server'

…utes/dashboard/course/$lessonId/edit.tsx …utes/dashboard.course.$lessonId.edit.tsxapp/routes/dashboard/course/$lessonId/edit.tsx renamed to app/routes/dashboard.course.$lessonId.edit.tsx app/routes/dashboard/course/$lessonId/edit.tsx renamed to app/routes/dashboard.course.$lessonId.edit.tsx

@@ -1,6 +1,6 @@
 import { VideoCameraIcon } from '@heroicons/react/outline'
 import { useOutletContext } from '@remix-run/react'
-import { CourseContextType } from '../course'
+import { CourseContextType } from './dashboard.course'
 
 export default function CourseIndex() {
   const { directory } = useOutletContext<CourseContextType>()