feat: v0.15.0

### Added

- **Layered event storage architecture.**  Each event now lands as four
  files in the per-serial waveform store, each with a clear role:

  - `<filename>` — the Blastware-readable binary (BW file).  Untouched.
  - `<filename>.a5.pkl` — the raw 5A frames (regenerative source).
  - `<filename>.h5` — clean per-channel waveform arrays in physical
    units (in/s for geo, psi for mic) plus event metadata (HDF5 with
    gzip compression).  This is the canonical format for downstream
    analysis tools.
  - `<filename>.sfm.json` — the modern review/metadata sidecar (peaks,
    project, source provenance, review state, extensions).

  SQLite (`seismo_relay.db`) is the searchable index over all four.

- **Plot-ready waveform JSON (`sfm.plot.v1`).**  The `/device/event/{idx}/waveform`
  and `/db/events/{id}/waveform.json` endpoints now return samples in
  physical units with explicit time-axis metadata, peak markers, and
  per-channel unit hints — no more guessing the ADC-to-velocity scale
  client-side.  The webapp waveform viewer was rewritten to consume
  this shape.

- **In-app waveform viewer accuracy fix.**  The standalone SFM webapp
  viewer was scaling geophone amplitudes by `geoAdcScale / 32767`
  (≈ 6.206 / 32767), where `geoAdcScale = 6.206053` is the device's
  *in/s per V* hardware constant — not the ADC-counts-to-velocity
  factor.  This silently scaled every plot ~38% too low for Normal-range
  geophones (the correct full-scale is 10.0 in/s, or 1.25 in/s for
  Sensitive).  Conversion is now done server-side using the geo_range
  from compliance config; the client just plots.

- New `sfm/event_hdf5.py` module: `write_event_hdf5()`,
  `read_event_hdf5()`, plus a plot-JSON helper.
- Backfill script extended to also emit `.h5` for existing events.

### Dependencies

- Added `h5py>=3.10` and `numpy>=1.24` for the HDF5 storage layer.
- Added `python-multipart>=0.0.7` (required by FastAPI for the
  `/db/import/blastware_file` endpoint introduced in this release).

requirements.txt

@@ -2,3 +2,6 @@ fastapi
 uvicorn
 sqlalchemy
 pyserial
+python-multipart
+h5py
+numpy