fix: parse diffs by word

inplace_chat.py

@@ -60,15 +60,17 @@ def summarize_edit(old: str, new: str) -> tuple[str, str]:
     Produce coarse 'removed_text' and 'edited_text' by joining all deletions and insertions.
     Good enough for a single bullet like: - Replaced {removed_text} with {edited_text}
     """
-    sm = difflib.SequenceMatcher(a=old, b=new)
+    old_words = old.split()
+    new_words = new.split()
+    sm = difflib.SequenceMatcher(a=old_words, b=new_words)
     removed_chunks, added_chunks = [], []
     for tag, i1, i2, j1, j2 in sm.get_opcodes():
         if tag in ("delete", "replace"):
-            chunk = old[i1:i2].strip()
+            chunk = " ".join(old_words[i1:i2]).strip()
             if chunk:
                 removed_chunks.append(chunk)
         if tag in ("insert", "replace"):
-            chunk = new[j1:j2].strip()
+            chunk = " ".join(new_words[j1:j2]).strip()
             if chunk:
                 added_chunks.append(chunk)
     removed_text = " / ".join(removed_chunks) if removed_chunks else "(none)"
@@ -80,18 +82,20 @@ def get_detailed_diff(old: str, new: str) -> list[dict]:
     Returns a list of diff chunks with tags: 'equal', 'delete', 'insert', 'replace'
     Each chunk has: {'tag': str, 'text': str}
     """
-    sm = difflib.SequenceMatcher(a=old, b=new)
+    old_words = old.split()
+    new_words = new.split()
+    sm = difflib.SequenceMatcher(a=old_words, b=new_words)
     diff_chunks = []
     for tag, i1, i2, j1, j2 in sm.get_opcodes():
         if tag == 'equal':
-            diff_chunks.append({'tag': 'equal', 'text': old[i1:i2]})
+            diff_chunks.append({'tag': 'equal', 'text': ' '.join(old_words[i1:i2])})
         elif tag == 'delete':
-            diff_chunks.append({'tag': 'delete', 'text': old[i1:i2]})
+            diff_chunks.append({'tag': 'delete', 'text': ' '.join(old_words[i1:i2])})
         elif tag == 'insert':
-            diff_chunks.append({'tag': 'insert', 'text': new[j1:j2]})
+            diff_chunks.append({'tag': 'insert', 'text': ' '.join(new_words[j1:j2])})
         elif tag == 'replace':
-            diff_chunks.append({'tag': 'delete', 'text': old[i1:i2]})
-            diff_chunks.append({'tag': 'insert', 'text': new[j1:j2]})
+            diff_chunks.append({'tag': 'delete', 'text': ' '.join(old_words[i1:i2])})
+            diff_chunks.append({'tag': 'insert', 'text': ' '.join(new_words[j1:j2])})
     return diff_chunks
 
 # === Render current conversation ===