feat(ppclock): 倒计时前缀文字位图（clock 拆包/calendar 990 序列）+ CLI --prefix/--show-calendar，102 测试全绿

src/ppclock/commands.py

@@ -51,7 +51,22 @@ async def upload_image(t, bw: bytes, red: bytes | None, *, small: bool,
     await t.write_epd(P.end_frame(small=small))
 
 
-async def countdown_set(t, d: datetime.date, mode: str):
+async def countdown_set(t, d: datetime.date, mode: str, prefix: str | None = None,
+                        show_calendar: bool = False):
+    """倒计时：前缀文字位图（可选）→ 日期帧 → E2。
+    show_calendar=True 走 upload_rili 序列：990* → FA → e10103 → E2（timedjs2.js:308-312）。"""
+    from . import textbitmap as TB
+    if prefix:
+        for frame in TB.prefix_frames(prefix, "calendar" if show_calendar else mode):
+            await t.write_rxtx(frame)
+            await t.delay(1.0)
+    if show_calendar:
+        await t.write_rxtx(bytes([0xFA]))
+        await t.delay(1.0)
+        await t.write_rxtx(P.mode_frame("calendar1"))
+        await t.delay(1.0)
+        await t.write_rxtx(P.simple_command("commit"))
+        return
     await t.write_rxtx(P.countdown_date_frame(d, mode))
     await t.delay(1.0)
     await t.write_rxtx(P.simple_command("commit"))