fix: enable unrar on all distros, not just Fedora (#1376)

* fix: enable unrar on all distros, not just Fedora

unrar was gated behind distro.id() == 'fedora', so on Debian/Ubuntu
the binary was installed but never invoked. Try unrar unconditionally
after 7z, with an optional rarfile Python fallback.

Fixes CBR extraction on non-Fedora Linux distributions.

* fix: gate unrar on Linux and drop unused distro dependency

Debian/Ubuntu's '7zip' package ships the upstream 7zz binary, which
excludes RAR support for licensing reasons, so 7z fails to read .cbr
(RAR) archives. unrar was installed but only invoked when
distro.id() == 'fedora', so on Debian it was never tried and extraction
failed.

Per maintainer feedback, gate unrar on platform.system() == 'Linux'
(not needed on Windows or macOS) and drop the rarfile PyPI fallback to
avoid a new dependency. Since the code no longer imports distro, also
remove it from the requirements files and setup.py.

kindlecomicconverter/comicarchive.py

@@ -22,7 +22,6 @@ from functools import cached_property, lru_cache
 import os
 from pathlib import Path
 import platform
-import distro
 from subprocess import STDOUT, PIPE, CalledProcessError
 from xml.dom.minidom import parseString
 from xml.parsers.expat import ExpatError
@@ -41,12 +40,12 @@ class ComicArchive:
         self.dirname, self.basename = os.path.split(filepath)
 
     @cached_property
-    def type(self):    
+    def type(self):
         extraction_commands = [
             [SEVENZIP, 'l', '-y', '-p1', self.basename],
         ]
 
-        if distro.id() == 'fedora' or distro.like() == 'fedora':
+        if platform.system() == 'Linux':
             extraction_commands.append(
                 ['unrar', 'l', '-y', '-p1', self.basename],
             )
@@ -85,20 +84,20 @@ class ComicArchive:
 
         extraction_commands.reverse()
 
-        if distro.id() == 'fedora' or distro.like() == 'fedora':
+        if platform.system() == 'Linux':
             extraction_commands.append(
                 ['unrar', 'x', '-y', '-x__MACOSX', '-x.DS_Store', '-xthumbs.db', '-xThumbs.db', self.basename, targetdir]
             )
-        
+
         for cmd in extraction_commands:
             try:
                 subprocess_run(cmd, capture_output=True, check=True, cwd=self.dirname)
-                return targetdir     
+                return targetdir
             except FileNotFoundError:
                 missing.append(cmd[0])
             except CalledProcessError:
                 pass
-        
+
         if missing:
             raise OSError(f'Extraction failed, install <a href="https://github.com/ciromattia/kcc#7-zip">specialized extraction software.</a>  ')
         else: