Fix proteome_name derivation to use Path.stem

Replace str(proteome).split('/')[-1].split('.')[0] with Path(...).stem in
Matcher and Preprocessor. The old logic truncated names at the first dot
(so human.v1.fasta and human.v2.fasta both mapped to 'human', colliding on
the same .pepidx index) and hardcoded '/' (breaking on Windows paths).

Author: dmx2

pepmatch/matcher.py

@@ -112,7 +112,7 @@ def __init__(
       raise ValueError('counts_only is not supported with best_match.')
 
     self.proteome_file = str(proteome_file)
-    self.proteome_name = str(proteome_file).split('/')[-1].split('.')[0]
+    self.proteome_name = Path(proteome_file).stem
     self.max_mismatches = max_mismatches
     self.preprocessed_files_path = preprocessed_files_path
     self.best_match = best_match

pepmatch/preprocessor.py

@@ -1,4 +1,5 @@
 import os
+from pathlib import Path
 from ._rs import rs_preprocess
 
 class Preprocessor:
@@ -20,7 +21,7 @@ def __init__(
     self.proteome_file = str(proteome)
 
     if not proteome_name:
-      self.proteome_name = str(proteome).split('/')[-1].split('.')[0]
+      self.proteome_name = Path(proteome).stem
     else:
       self.proteome_name = proteome_name