v0.2.0

Breaking change to the typed Log.<modality> accessors plus a
parse-time fix for same-rate sample-count drift. Bumped to 0.2.0
under the "breaking change → minor on 0.x" semver-on-0.x convention.

Changed (BREAKING)

• Log.emg / Log.ekg / Log.acc / Log.gyro / Log.fsr /
  Log.analog / Log.vo2master / Log.hrstrap now return a single
  aggregated pysampled.Data per modality (channels stacked across
  every sensor that carries the modality), or None if no sensor
  does. Previously each returned a List[Bundle] (one entry per
  sensor). Use bundle.split_by_signal_name() to recover the
  per-sensor list.
• EMG.process(amp_kind="nk") and EKG.find_rpeaks_pn now raise
  NotImplementedError on multi-channel input with a hint to use
  split_by_signal_name. Previously both silently flattened
  column-major and produced nonsense.
• FSR.a / .b / .c / .d raise NotImplementedError on
  aggregate FSR (≠ 4 channels) since "the 4th channel" is meaningless
  across heterogeneous sensors. The per-Sensor 4-channel view is
  unchanged.

Added

• _normalize_signal_lengths — same-rate length-drift normalization
  in _util.py, called from Log.__init__ between parser dispatch
  and the per-Sensor stack. Tail-trims each (modality, sr) group to
  its shortest length so floating-point drift from the per-format
  resample step no longer trips Sensor's same-modality length
  assert. Drift exceeding _DRIFT_TOLERANCE (4 samples) emits a
  UserWarning.
• _aggregate_bundles helper — stacks per-Sensor bundles along the
  signal axis, validates signal_coords/axis/t0 agreement, and
  downsamples higher-rate parts to the lowest sampling rate (with
  UserWarning) when the input is multi-rate within one modality.
• bundle.sensors (plural) property on every modality bundle
  (Signal, IMU, FSR, VO2Master, EMG, EKG). Returns the
  aggregate's meta["sensors"] list when present, else
  [meta["sensor"]] for the per-Sensor case (length 1).
• meta["sensors"] convention on aggregate bundles, aligned with
  signal_names (so len(bundle.meta["sensors"]) == len(bundle.signal_names)).

Fixed

• IMU.x / .y / .z use coord-lookup (s["x"]) instead of
  positional column slicing, so the same accessor works on per-Sensor
  IMU (n, 3) and aggregate IMU (n, 3*N). The previous positional
  slice silently returned only the first sensor's column on multi-
  sensor input.

Internal

• Moved _SUBCHANNEL_KEYS (FSR / Quattro channelmap parenthetical
  key format) from _util.py to _constants.py alongside
  SUBCHANNEL_MAP. No public API change.

Migration

Before (0.1.x)	After (0.2.0)
for emg in lf.emg:	for emg in lf.emg.split_by_signal_name():
lf.acc[0].magnitude()	lf.acc.split_by_signal_name()[0].magnitude()
len(lf.emg)	len(lf.emg.signal_names) if lf.emg else 0
if lf.acc:	if lf.acc is not None:
lf.acc[0]	lf.acc.split_by_signal_name()[0]
lf.fsr('')[1]	lf.fsr.split_by_signal_name()[1] (or by name)

Downstream consumers that iterate Log.<modality> lists need updating;
consumers that use Sensor.<modality> (per-Sensor view) are unchanged.

Provenance

The accessor reshape and the drift fix are coupled: one bundle per
modality only makes sense if every sensor's channels for that modality
end up at identical post-resample lengths. The smoking-gun pickle is
at C:/dev/immersionToolbox/_data/_resampling numbers/, where two
ACC channels nominally at the same rate ended up 1 sample apart
because of a Trigno frame quantization boundary. Centralizing the fix
post-parse keeps the per-format parsers' quirks intact.