v2.0.1 macOS launchers & pandas 2.x session fix

[2.0.1] - 2026-04-08

Fixed

• Session save/load: wrap DataFrame JSON string in io.StringIO before passing to
  pd.read_json(), fixing a FileNotFoundError on pandas 2.x where a bare string
  argument is now treated as a file path rather than inline content
  (modules/utils/session_state.py)

Changed

• Added macOS one-click setup and launch scripts (setup.command, launch.command)
• Updated launch.bat to check for the virtual environment and print a helpful error
  if it is missing
• README: added platform-specific setup/launch instructions, PyPI badge, and updated
  programmatic import examples to use plottle.* namespace
• pyproject.toml: bumped minimum setuptools to 78.0, normalized license field
  to PEP 639 format, corrected author email, added build/twine dev dependencies
  and changelog URL
• modules/Home.py: use .resolve() for path construction (improves symlink and
  working-directory robustness); moved NCCU wings logo to sidebar