fix(review): address PR #318 review feedback

- entry.py: add standard "# Copyright 2026 Cloudsmith Ltd" header
  (Copilot) — matches the convention used by other new modules.
- cloudsmith.spec: add the same header after the mode/coding magic line
  (Copilot).
- Declined (Copilot, spec lines 12 & 35): "Analysis(['entry.py']) will
  fail when PyInstaller runs from the repo root." PyInstaller resolves
  relative script paths in Analysis() against the spec file's directory
  (SPECPATH), not the CWD. Reproduced a full build from the repo root
  (the exact workflow invocation) — PyInstaller logged
  "Analyzing .../packaging/pyinstaller/entry.py" and the build
  completed successfully. No HERE/pathex change needed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: BartoszBlizniak

packaging/pyinstaller/cloudsmith.spec

@@ -1,4 +1,5 @@
 # -*- mode: python ; coding: utf-8 -*-
+# Copyright 2026 Cloudsmith Ltd
 # PyInstaller onedir spec for the Cloudsmith CLI. Built natively per target.
 # onedir (not onefile): onefile re-extracts the whole bundle on every
 # invocation (~6s/run); onedir starts in ~0.4s. Distributed as tar.gz/zip.

packaging/pyinstaller/entry.py

@@ -1,3 +1,4 @@
+# Copyright 2026 Cloudsmith Ltd
 import importlib
 import os
 import pkgutil