Fix FileStorage on Windows: open fd with O_BINARY, UTF-8 release logs

os.open() on Windows defaults to O_TEXT, so the CRT translated \r\n in
binary ciphertext: writes grew, offsets shifted, reads came up short and
the RAF callbacks failed with EIO (probe/read/write depending on where
a 0x0A byte landed). Pass O_BINARY where it exists.

Also reconfigure stdout/stderr to UTF-8 in tools/release.py so the
✓/✗/⚠ summary lines don't crash on cp1252 Windows consoles.

src/aeg/raf.py

@@ -104,6 +104,9 @@ class FileStorage:
             flags = os.O_RDWR | os.O_CREAT | os.O_EXCL
         else:
             raise ValueError(f"Unsupported mode: {mode}")
+        # O_BINARY (Windows only): keep the CRT from translating \r\n in
+        # binary data, which corrupts ciphertext and shifts offsets
+        flags |= getattr(os, "O_BINARY", 0)
         self._fd = os.open(path, flags, 0o644)
         self._closed = False
         self._lock = threading.Lock()