refactor: Use difflib.SequenceMatcher for improved line matching logic

gtm

@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 
 import curses
+import difflib
 import os
 import subprocess
 import sys
@@ -33,30 +34,26 @@ def find_best_matching_line(reference_line, file_lines, max_lines=None):
         if line == reference_line:
             return i
             
-    # If no exact match, try to find the most similar line
+    # If no exact match, use difflib to find the most similar line
     # Only search through a reasonable number of lines for performance
     search_lines = file_lines[:max_lines] if max_lines else file_lines
     
-    best_match = None
-    best_score = 0
+    best_match_idx = None
+    best_ratio = 0.0
+    
+    # Create a SequenceMatcher for the reference line, but reuse it for efficiency
+    s = difflib.SequenceMatcher(None, reference_line)
     
     for i, line in enumerate(search_lines):
-        # Simple similarity score: count of common characters
-        score = sum(1 for a, b in zip(reference_line, line) if a == b)
-        
-        # Adjust score based on length difference
-        length_diff = abs(len(reference_line) - len(line))
-        adjusted_score = score - (length_diff * 0.5)
-        
-        if adjusted_score > best_score:
-            best_score = adjusted_score
-            best_match = i
+        s.set_seq2(line)
+        ratio = s.ratio()
+        if ratio > best_ratio:
+            best_ratio = ratio
+            best_match_idx = i
             
-    # Only return a match if it's reasonably good
-    # (at least 60% of the shorter string length)
-    min_length = min(len(reference_line), 1)  # Avoid division by zero
-    if best_score > (min_length * 0.6):
-        return best_match
+    # Only return a match if it's reasonably good (e.g., ratio > 0.6)
+    if best_ratio > 0.6:
+        return best_match_idx
         
     return None