pip's data_files extraction is unreliable for user installs with
--break-system-packages: files either land in the wrong prefix or are
silently dropped from the wheel entirely.

Fix: build_py hook in setup.py copies main.py, aisbf.sh, requirements.txt,
templates/, static/, and config/ into aisbf/_share/ at wheel-build time.
These are declared as package_data so pip always installs them to
site-packages/aisbf/_share/ regardless of install mode.

cli.py now:
- Checks all sysconfig-derived paths for a complete share directory
- Falls back to bootstrapping: copies the full aisbf/_share/ bundle to
  ~/.local/share/aisbf/ on first run if data_files were not installed
- Works for both wheel installs (uses _share/) and editable installs
  (uses the project root directly as the bundle source)
- Prints a clear error with checked paths and reinstall instructions if
  bootstrap also fails

aisbf/_share/ is gitignored (generated at build time).