fix: use HM42 vendor image upload session

src/ppclock/protocol.py

@@ -40,6 +40,28 @@ def requires_complete_image_planes(firmware_revision: str | None) -> bool:
     revision = (firmware_revision or "").strip().upper()
     return revision.startswith("HM42_AIO")
 
+
+def uses_hm42_image_session(firmware_revision: str | None) -> bool:
+    """Whether image transfer needs the newer HM42 EPD session framing.
+
+    The vendor Android provider ``轻舞/时光`` (``d8.e``) wraps both image
+    planes with ``8001, 0000, 020000`` and closes with ``0101`` followed by
+    RXTX ``e2`` for a normal (non-calendar) image.  The older Web-BLE path has
+    no such preamble and ends with the legacy one-byte EPD frame.
+    """
+    revision = (firmware_revision or "").strip().upper()
+    return revision.startswith("HM42_AIO")
+
+
+def hm42_image_begin_frames() -> tuple[bytes, ...]:
+    """Vendor-app EPD image-session preamble for HM42_AIO firmware."""
+    return (bytes.fromhex("8001"), bytes.fromhex("0000"), bytes.fromhex("020000"))
+
+
+def hm42_image_finish_frame() -> bytes:
+    """Vendor-app EPD image-session terminator for HM42_AIO firmware."""
+    return bytes.fromhex("0101")
+
 MODES = {
     **{f"image{i}": bytes([0xE1, 0x00, 0x00 + i]) for i in range(4)},
     "calendar1": bytes.fromhex("e10103"),