Fix startup crash on setuptools 81+ (drop pkg_resources)

[kapshytar]

Problem

The app crashes on launch with:

ModuleNotFoundError: No module named 'pkg_resources'

setuptools 81 removed the long-deprecated bundled pkg_resources module, and modern virtualenvs (setuptools 81+) no longer ship it. Since core/configurations.py imports resource_filename from pkg_resources, the app no longer starts on a fresh, up-to-date environment (e.g. Python 3.12 + setuptools 82). The only workaround today is pinning setuptools<81.

Fix

Replace the single pkg_resources.resource_filename import with a tiny standard-library shim built on importlib.resources (available since Python 3.9). All ~30 call sites are left untouched:

from importlib.resources import files as _resource_files

def resource_filename(package: str, resource: str) -> str:
    return str(_resource_files(package).joinpath(resource))

This resolves the same packages (app, resources.styles, resources.icons, …) to filesystem paths, including the namespace packages without __init__.py.

Also:

• Re-encoded requirements.txt as UTF-8 (it was UTF-16, which trips some tools).
• Relaxed the stale pins to current releases (PyQt5, adb-shell[usb]); transitive deps are resolved automatically.

Testing

Launched on Python 3.12 with setuptools 82.0.1 (where import pkg_resources raises ModuleNotFoundError). The app now starts, lists the device, browses folders (including names with spaces) and downloads files — no pkg_resources, no setuptools<81 pin needed.