fix(lf): correct T55xx write/wakeup structs, 2-byte LF tune, fire-and-forget sampling config

lf.tune sends the 2-byte {mode,divisor} the firmware requires (was 3 -> EINVARG/0V). t55.writebl packs the 10-byte {data,pwd,blockno,flags} struct with a single bit-packed flags byte (was 12). t55.wakeup packs 5 bytes {pwd,flags}. t55.config is maintained client-side (firmware has no GET). LF_SAMPLING_SET_CONFIG uses send_ng_no_response (firmware never replies). Pre-existing, independent of the rebase.

tests/test_lf.py

@@ -11,11 +11,15 @@ def make_response(cmd, status, data):
 def test_lf_tune():
     t = AsyncMock()
     lf = LFCommands(t)
-    # First call: init, second call: poll returns data
+    # First call: init, second call: measure returns uint32 voltage
     t.send_ng.return_value = make_response(Cmd.MEASURE_ANTENNA_TUNING_LF, 0,
                                            struct.pack("<I", 42000))
     result = asyncio.get_event_loop().run_until_complete(lf.tune(divisor=95))
-    assert "voltage_mV" in result
+    assert result["voltage_mV"] == 42000
+    # Firmware requires exactly 2-byte payloads ({1,div} init, {2,div} measure)
+    calls = t.send_ng.call_args_list
+    assert calls[0].args[1] == struct.pack("<BB", 1, 95)
+    assert calls[1].args[1] == struct.pack("<BB", 2, 95)
 
 def test_lf_config_get():
     t = AsyncMock()
@@ -25,3 +29,50 @@ def test_lf_config_get():
     result = asyncio.get_event_loop().run_until_complete(lf.config())
     assert "decimation" in result
     assert "bits_per_sample" in result
+
+def test_lf_config_set_fire_and_forget():
+    t = AsyncMock()
+    lf = LFCommands(t)
+    payload = struct.pack("<bbbhhib", 1, 8, 1, 95, 128, 0, 0)
+    t.send_ng.return_value = make_response(Cmd.LF_SAMPLING_GET_CONFIG, 0, payload)
+    asyncio.get_event_loop().run_until_complete(lf.config(divisor=88))
+    # Firmware never replies to SET — must be fire-and-forget
+    t.send_ng_no_response.assert_awaited_once()
+    assert t.send_ng_no_response.call_args.args[0] == Cmd.LF_SAMPLING_SET_CONFIG
+
+def test_lf_t55_writebl():
+    t = AsyncMock()
+    lf = LFCommands(t)
+    t.send_ng.return_value = make_response(Cmd.LF_T55XX_WRITEBL, 0, b"")
+    asyncio.get_event_loop().run_until_complete(
+        lf.t55.writebl(block=4, data=0x12345678, page=1,
+                       password=0xAABBCCDD, downlink_mode=2))
+    payload = t.send_ng.call_args.args[1]
+    # data(4)+pwd(4)+blockno(1)+flags(1) = 10 bytes
+    assert len(payload) == 10
+    data, pwd, blockno, flags = struct.unpack("<IIBB", payload)
+    assert data == 0x12345678
+    assert pwd == 0xAABBCCDD
+    assert blockno == 4
+    # PwdMode(0x01) | Page(0x02) | downlink 2<<3 (0x10) = 0x13
+    assert flags == 0x13
+
+def test_lf_t55_wakeup():
+    t = AsyncMock()
+    lf = LFCommands(t)
+    t.send_ng.return_value = make_response(Cmd.LF_T55XX_WAKEUP, 0, b"")
+    asyncio.get_event_loop().run_until_complete(
+        lf.t55.wakeup(password=0x11223344, downlink_mode=3))
+    payload = t.send_ng.call_args.args[1]
+    assert len(payload) == 5
+    pwd, flags = struct.unpack("<IB", payload)
+    assert pwd == 0x11223344
+    assert flags == (3 << 3)
+
+def test_lf_t55_config_client_side():
+    t = AsyncMock()
+    lf = LFCommands(t)
+    result = asyncio.get_event_loop().run_until_complete(lf.t55.config())
+    assert len(result["modes"]) == 4
+    # No firmware round-trip: SET_CONFIG is write-only and never replies
+    t.send_ng.assert_not_called()