[App] Moved app.py to root dir for lightning init app <app_name> template

docs/source-app/workflows/build_lightning_app/from_scratch_content.rst

@@ -87,10 +87,10 @@ You'll see a print-out like this:
         /Users/Your/Current/dir/your-app-name
 
     run your app with:
-        lightning run app your-app-name/your_app_name/app.py
+        lightning run app your-app-name/app.py
 
     run it on the cloud to share with your collaborators:
-        lightning run app your-app-name/your_app_name/app.py --cloud
+        lightning run app your-app-name/app.py --cloud
 
 ----
 

src/lightning_app/CHANGELOG.md

@@ -26,3 +26,4 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 ### Fixed
 
 - Resolved a bug where the work statuses will grow quickly and be duplicated ([#13970](https://github.com/Lightning-AI/lightning/pull/13970))
+- Unification of app template: moved `app.py` to root dir for `lightning init app <app_name>` template ([#13853](https://github.com/Lightning-AI/lightning/pull/13853))

src/lightning_app/cli/cmd_init.py

@@ -19,10 +19,10 @@ def app(app_name):
     {new_resource_name}
 
     run your app with:
-        lightning run app {app_name}/{name_for_files}/app.py
+        lightning run app {app_name}/app.py
 
     run it on the cloud to share with your collaborators:
-        lightning run app {app_name}/{name_for_files}/app.py --cloud
+        lightning run app {app_name}/app.py --cloud
     """
     logger.info(m)