fix: use UTF-8 for text file operations

agents/s06_context_compact.py

@@ -104,7 +104,7 @@ def auto_compact(messages: list, focus: str = "") -> list:
     # Save full transcript to disk
     TRANSCRIPT_DIR.mkdir(exist_ok=True)
     transcript_path = TRANSCRIPT_DIR / f"transcript_{int(time.time())}.jsonl"
-    with open(transcript_path, "w") as f:
+    with open(transcript_path, "w", encoding="utf-8") as f:
         for msg in messages:
             f.write(json.dumps(msg, default=str) + "\n")
     print(f"[transcript saved: {transcript_path}]")
@@ -152,7 +152,7 @@ def run_bash(command: str) -> str:
 
 def run_read(path: str, limit: int = None) -> str:
     try:
-        lines = safe_path(path).read_text().splitlines()
+        lines = safe_path(path).read_text(encoding="utf-8").splitlines()
         if limit and limit < len(lines):
             lines = lines[:limit] + [f"... ({len(lines) - limit} more)"]
         return "\n".join(lines)[:50000]
@@ -163,7 +163,7 @@ def run_write(path: str, content: str) -> str:
     try:
         fp = safe_path(path)
         fp.parent.mkdir(parents=True, exist_ok=True)
-        fp.write_text(content)
+        fp.write_text(content, encoding="utf-8")
         return f"Wrote {len(content)} bytes"
     except Exception as e:
         return f"Error: {e}"
@@ -171,10 +171,10 @@ def run_write(path: str, content: str) -> str:
 def run_edit(path: str, old_text: str, new_text: str) -> str:
     try:
         fp = safe_path(path)
-        content = fp.read_text()
+        content = fp.read_text(encoding="utf-8")
         if old_text not in content:
             return f"Error: Text not found in {path}"
-        fp.write_text(content.replace(old_text, new_text, 1))
+        fp.write_text(content.replace(old_text, new_text, 1), encoding="utf-8")
         return f"Edited {path}"
     except Exception as e:
         return f"Error: {e}"