fix: serial decode offset, PPV label scan, debug mode for waveform records

- _decode_serial_number: read from data[11:] not data[:8] — was returning
  the LENGTH_ECHO byte (0x0A = '\n') instead of the serial string
- _extract_peak_floats: search for channel label strings ("Tran" etc) and
  read float at label+6; old step-4 aligned scan was reading trigger levels
  instead of PPV values
- get_events: add debug=False param; stashes raw 210-byte record on
  Event._raw_record when True for field-layout inspection
- server /device/events: add ?debug=true query param; includes
  raw_record_hex + raw_record_len in response when set
- models: add Event._raw_record optional bytes field

minimateplus/client.py

@@ -145,7 +145,7 @@ class MiniMateClient:
         log.info("connect: %s", device_info)
         return device_info
 
-    def get_events(self, include_waveforms: bool = True) -> list[Event]:
+    def get_events(self, include_waveforms: bool = True, debug: bool = False) -> list[Event]:
         """
         Download all stored events from the device using the confirmed
         1E → 0A → 0C → 1F event-iterator protocol.
@@ -218,6 +218,8 @@ class MiniMateClient:
                 # SUB 0C — full waveform record (peak values, project strings)
                 try:
                     record = proto.read_waveform_record(key4)
+                    if debug:
+                        ev._raw_record = record
                     _decode_waveform_record_into(record, ev)
                 except ProtocolError as exc:
                     log.warning(
@@ -262,14 +264,19 @@ def _decode_serial_number(data: bytes) -> DeviceInfo:
     Returns:
         New DeviceInfo with serial, firmware_minor, serial_trail_0 populated.
     """
-    if len(data) < 9:
+    # data is data_rsp.data = payload[5:].  The 11-byte section header occupies
+    # data[0..10]: [LENGTH_ECHO:1][00×4][KEY_ECHO:4][00×2].
+    # Actual serial payload starts at data[11].
+    actual = data[11:] if len(data) > 11 else data
+
+    if len(actual) < 9:
         # Short payload — gracefully degrade
-        serial = data.rstrip(b"\x00").decode("ascii", errors="replace")
+        serial = actual.rstrip(b"\x00").decode("ascii", errors="replace")
         return DeviceInfo(serial=serial, firmware_minor=0)
 
-    serial = data[:8].rstrip(b"\x00").decode("ascii", errors="replace")
-    trail_0 = data[8] if len(data) > 8 else None
-    fw_minor = data[9] if len(data) > 9 else 0
+    serial = actual[:8].rstrip(b"\x00").decode("ascii", errors="replace")
+    trail_0 = actual[8] if len(actual) > 8 else None
+    fw_minor = actual[9] if len(actual) > 9 else 0
 
     return DeviceInfo(
         serial=serial,

minimateplus/models.py

@@ -197,6 +197,11 @@ class Event:
     # requested (large data transfer — up to several MB per event).
     raw_samples: Optional[dict] = None      # {"Tran": [...], "Vert": [...], ...}
 
+    # ── Debug / introspection ─────────────────────────────────────────────────
+    # Raw 210-byte waveform record bytes, set when debug mode is active.
+    # Exposed by the SFM server via ?debug=true so field layouts can be verified.
+    _raw_record: Optional[bytes] = field(default=None, repr=False)
+
     def __str__(self) -> str:
         ts = str(self.timestamp) if self.timestamp else "no timestamp"
         ppv = ""