Update main README and hello-world README

[allison-truhlar]

• Minor edits/reorganization in main README and hello-world README for clarity on how to get started, specifically for a new user for the repo.
• Suggests two command changes in the hello-world README to fix error messages

[fcollonval]

Thanks a lot @allison-truhlar I got a minor question.

Would you also monde updating the sentence:

The first command installs the dependencies that are specified in the
setup.py file and in package.json.

To mention pyproject.toml instead of setup.py?

[fcollonval]

Just to be sure, you needed that step to install that example specifically from the examples repository?

[allison-truhlar]

Yes, without it I get this warning when running pip install -e .:

(jupyterlab-extension-examples) truhlara@truhlara-lm1 my_extension % pip install -e .
Obtaining file:///Users/truhlara/dev/test-jupyterlab-extension-examples/my_extension
  Installing build dependencies ... done
  Checking if build backend supports build_editable ... done
  Getting requirements to build editable ... done
  Installing backend dependencies ... done
  Preparing editable metadata (pyproject.toml) ... error
  error: subprocess-exited-with-error
  
  × Preparing editable metadata (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [49 lines of output]
      INFO:hatch_jupyter_builder.utils:Running jupyter-builder
      INFO:hatch_jupyter_builder.utils:Building with hatch_jupyter_builder.npm_builder
      INFO:hatch_jupyter_builder.utils:With kwargs: {'build_cmd': 'install:extension', 'npm': ['jlpm'], 'source_dir': 'src', 'build_dir': 'myextension/labextension'}
      INFO:hatch_jupyter_builder.utils:Installing build dependencies with npm.  This may take a while...
      INFO:hatch_jupyter_builder.utils:> /private/var/folders/lk/8y24cj3920l4yp9mzzjcw0z00000gq/T/pip-build-env-9ud29507/overlay/bin/jlpm install
      Usage Error: The nearest package directory (/Users/truhlara/dev/test-jupyterlab-extension-examples/my_extension) doesn't seem to be part of the project declared in /Users/truhlara/dev/test-jupyterlab-extension-examples.
      
      - If /Users/truhlara/dev/test-jupyterlab-extension-examples isn't intended to be a project, remove any yarn.lock and/or package.json file there.
      - If /Users/truhlara/dev/test-jupyterlab-extension-examples is intended to be a project, it might be that you forgot to list my_extension in its workspace configuration.
      - Finally, if /Users/truhlara/dev/test-jupyterlab-extension-examples is fine and you intend my_extension to be treated as a completely separate project (not even a workspace), create an empty yarn.lock file in it.
      
      $ yarn install [--json] [--immutable] [--immutable-cache] [--check-cache] [--inline-builds] [--mode #0]
      Traceback (most recent call last):
        File "/Users/truhlara/miniconda3/envs/jupyterlab-extension-examples/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 167, in prepare_metadata_for_build_editable
          hook = backend.prepare_metadata_for_build_editable
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      AttributeError: module 'hatchling.build' has no attribute 'prepare_metadata_for_build_editable'
      
      During handling of the above exception, another exception occurred:
      
      Traceback (most recent call last):
        File "/Users/truhlara/miniconda3/envs/jupyterlab-extension-examples/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
          ~~~~^^
        File "/Users/truhlara/miniconda3/envs/jupyterlab-extension-examples/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 335, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
                                   ~~~~^^^^^^^^^^^^^^^^^^^^^^^^
        File "/Users/truhlara/miniconda3/envs/jupyterlab-extension-examples/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 176, in prepare_metadata_for_build_editable
          whl_basename = build_hook(metadata_directory, config_settings)
        File "/private/var/folders/lk/8y24cj3920l4yp9mzzjcw0z00000gq/T/pip-build-env-9ud29507/overlay/lib/python3.13/site-packages/hatchling/build.py", line 83, in build_editable
          return os.path.basename(next(builder.build(directory=wheel_directory, versions=['editable'])))
                                  ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/private/var/folders/lk/8y24cj3920l4yp9mzzjcw0z00000gq/T/pip-build-env-9ud29507/overlay/lib/python3.13/site-packages/hatchling/builders/plugin/interface.py", line 147, in build
          build_hook.initialize(version, build_data)
          ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
        File "/private/var/folders/lk/8y24cj3920l4yp9mzzjcw0z00000gq/T/pip-build-env-9ud29507/normal/lib/python3.13/site-packages/hatch_jupyter_builder/plugin.py", line 94, in initialize
          raise e
        File "/private/var/folders/lk/8y24cj3920l4yp9mzzjcw0z00000gq/T/pip-build-env-9ud29507/normal/lib/python3.13/site-packages/hatch_jupyter_builder/plugin.py", line 89, in initialize
          build_func(self.target_name, version, **build_kwargs)
          ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/private/var/folders/lk/8y24cj3920l4yp9mzzjcw0z00000gq/T/pip-build-env-9ud29507/normal/lib/python3.13/site-packages/hatch_jupyter_builder/utils.py", line 115, in npm_builder
          run([*npm_cmd, "install"], cwd=str(abs_path))
          ~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/private/var/folders/lk/8y24cj3920l4yp9mzzjcw0z00000gq/T/pip-build-env-9ud29507/normal/lib/python3.13/site-packages/hatch_jupyter_builder/utils.py", line 231, in run
          return subprocess.check_call(cmd, **kwargs)
                 ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
        File "/Users/truhlara/miniconda3/envs/jupyterlab-extension-examples/lib/python3.13/subprocess.py", line 419, in check_call
          raise CalledProcessError(retcode, cmd)
      subprocess.CalledProcessError: Command '['/private/var/folders/lk/8y24cj3920l4yp9mzzjcw0z00000gq/T/pip-build-env-9ud29507/overlay/bin/jlpm', 'install']' returned non-zero exit status 1.
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.

[allison-truhlar]

Would you also monde updating the sentence:

The first command installs the dependencies that are specified in the
setup.py file and in package.json.

To mention pyproject.toml instead of setup.py?

@fcollonval Sure! I did this in the most recent commit, da86708