升级 Trellis 并完成项目审查（07-26-trellis-upgrade-project-audit）

.trellis/scripts/common/io.py

@@ -8,6 +8,8 @@ for JSON file operations across all Trellis scripts.
 from __future__ import annotations
 
 import json
+import os
+import tempfile
 from pathlib import Path
 
 
@@ -25,13 +27,35 @@ def read_json(path: Path) -> dict | None:
 def write_json(path: Path, data: dict) -> bool:
     """Write dict to JSON file with pretty formatting.
 
+    The write is atomic: content goes to a temp file in the same directory
+    and is then renamed over the target. A crash or Ctrl-C mid-write leaves
+    the existing file intact rather than truncated, so a corrupted task.json
+    can never make a task silently vanish from `task.py list`.
+
     Returns True on success, False on error.
     """
+    payload = json.dumps(data, indent=2, ensure_ascii=False)
     try:
-        path.write_text(
-            json.dumps(data, indent=2, ensure_ascii=False),
-            encoding="utf-8",
+        fd, tmp = tempfile.mkstemp(
+            dir=str(path.parent), prefix=f".{path.name}.", suffix=".tmp"
         )
+    except OSError:
+        return False
+
+    try:
+        try:
+            f = os.fdopen(fd, "w", encoding="utf-8")
+        except OSError:
+            # fdopen never took ownership of fd; close it ourselves.
+            os.close(fd)
+            raise
+        with f:
+            f.write(payload)
+        os.replace(tmp, path)
         return True
-    except (OSError, IOError):
+    except OSError:
+        try:
+            os.unlink(tmp)
+        except OSError:
+            pass
         return False