minimateplus: wire read_blastware_file to verified body codec

`read_blastware_file()` was still calling `_decode_samples_4ch_int16_le`
(the retracted int16-LE-interleaved hypothesis) on the body bytes,
producing ±32K noise on every channel of every BW file read from disk.
This was the path watcher-forwarded events take into the system
(via the import endpoint → save_imported_bw → read_blastware_file,
since the watcher doesn't ship A5 frames), so every .h5 sidecar
generated for a forwarded event has been wrong since the feature
shipped.

The fix is mechanical: pass the body bytes straight to
`waveform_codec.decode_waveform_v2()` and run the result through
`decoded_to_adc_counts()` for the 16x geo scaling.  The body already
starts with the codec's exact 7-byte preamble `00 02 00 [Tran[0] BE]
[Tran[1] BE]` — confirmed by `body[:3].hex()` across all 9 fixture
events.  No body-slice adjustment needed.

If the codec returns None (truncated/malformed file, synthetic test
input with no real waveform), fall back to empty channels with a log
warning.  The rest of the event (timestamp, waveform_key, project
strings, sensor_location, peaks-from-samples=0) is still recoverable.

Verified against the bundled fixture corpus:

  V70  Tran/Vert/Long 3328/3328 sample-sets match .TXT ground truth
       within the 0.005 in/s display quantum, every row
  6S0/RG0/AB0/470 (5-8-26)  3328/2304/1280/1280 samples; Vert PPVs
       match BW's own report within 0.02 in/s
  JQ0  3328 samples, Vert PPV 3.384 vs BW 3.465
  SP0/SS0/SV0 (loud events)  3072–3328 samples; known walker
       tail-truncation 1–7 samples per channel, samples reached are
       byte-exact

Existing `test_read_blastware_file_round_trip` (synthetic empty event)
continues to pass thanks to the None-fallback.  Codec verify scripts
(`analysis/verify_quiet_bundle.py`, `analysis/verify_full_decode.py`)
re-run unchanged.

Added two regression-lock tests in tests/test_event_file_io.py:
  - test_read_blastware_file_decodes_via_codec[6 fixtures]
    — verifies sample count + Vert PPV per fixture
  - test_read_blastware_file_v70_samples_match_txt_truth
    — verifies every one of V70's 3328 sample-sets across Tran/Vert/Long
      matches the .TXT ground truth row-by-row within 0.003 in/s

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_event_file_io.py

@@ -294,6 +294,97 @@ def test_read_blastware_file_round_trip(tmp_path: Path):
     assert parsed.peak_values.peak_vector_sum == 0.0
 
 
+_BW_CODEC_FIXTURES = [
+    # (path, expected_n_samples_per_channel, BW-reported Vert PPV in/s for sanity)
+    ("tests/fixtures/decode-re-5-8-26/event-a/M529LKVQ.6S0", 3328, 0.780),
+    ("tests/fixtures/decode-re-5-8-26/event-b/M529LK5Q.RG0", 2304, 0.505),
+    ("tests/fixtures/decode-re-5-8-26/event-c/M529LK44.AB0", 1280, 0.610),
+    ("tests/fixtures/decode-re-5-8-26/event-d/M529LK2V.470", 1280, 0.565),
+    ("tests/fixtures/5-11-26/M529LL1L.V70",                  3328, 0.010),
+    ("tests/fixtures/5-11-26/M529LL1L.JQ0",                  3328, 3.465),
+]
+
+
+@pytest.mark.parametrize("path,expected_n,expected_ppv", _BW_CODEC_FIXTURES)
+def test_read_blastware_file_decodes_via_codec(path: str, expected_n: int, expected_ppv: float):
+    """Regression lock: ``read_blastware_file()`` must use the verified
+    waveform-body codec (``minimateplus.waveform_codec``), not the
+    retracted int16-LE assumption.
+
+    Verifies against the real BW fixture corpus: every event in the
+    bundled fixtures must produce the expected per-channel sample count
+    and a Vert PPV close to BW's own reported value.  Catches any
+    accidental regression of the body decoder back to the old
+    ``_decode_samples_4ch_int16_le`` path (which produced ±32K noise
+    on every event, giving wildly wrong PPVs).
+    """
+    repo_root = Path(__file__).resolve().parent.parent
+    full_path = repo_root / path
+    if not full_path.exists():
+        pytest.skip(f"fixture missing: {full_path}")
+
+    ev = event_file_io.read_blastware_file(full_path)
+    assert ev.raw_samples is not None
+    for ch in ("Tran", "Vert", "Long"):
+        assert len(ev.raw_samples[ch]) == expected_n, (
+            f"{ch}: expected {expected_n} samples, got {len(ev.raw_samples[ch])}"
+        )
+
+    # PPV check: the codec produces decoded samples in 1-count ADC units;
+    # _peaks_from_samples scales by GEO_NORMAL_FS_INS / 32767.  BW's own
+    # PPV is computed at slightly different precision/interpolation, so
+    # we allow a 0.2 in/s tolerance — well under the broken-decoder
+    # signature (which would produce ~10 in/s saturation).
+    assert ev.peak_values is not None
+    assert abs(ev.peak_values.vert - expected_ppv) < 0.2, (
+        f"Vert PPV {ev.peak_values.vert:.3f} differs from BW's "
+        f"{expected_ppv:.3f} by >0.2 in/s — codec regression?"
+    )
+
+
+def test_read_blastware_file_v70_samples_match_txt_truth():
+    """Strongest regression lock: every one of V70's 3328 decoded
+    sample-sets must match the .TXT ground truth table within the
+    0.005 in/s display quantum."""
+    repo_root = Path(__file__).resolve().parent.parent
+    bw_path  = repo_root / "tests/fixtures/5-11-26/M529LL1L.V70"
+    txt_path = repo_root / "tests/fixtures/5-11-26/M529LL1L.V70.TXT"
+    if not bw_path.exists() or not txt_path.exists():
+        pytest.skip(f"V70 fixture missing")
+
+    import re
+    ev = event_file_io.read_blastware_file(bw_path)
+
+    # Parse .TXT ground truth sample table
+    text = txt_path.read_text()
+    lines = text.splitlines()
+    hdr_idx = next(i for i, line in enumerate(lines)
+                   if re.match(r"^Tran\s+Vert\s+Long\s+MicL?", line.strip()))
+    truth = []
+    for line in lines[hdr_idx + 1:]:
+        parts = line.strip().split()
+        if len(parts) != 4:
+            continue
+        try:
+            truth.append([float(x) for x in parts])
+        except ValueError:
+            continue
+    assert len(truth) == 3328, f"expected 3328 truth rows, got {len(truth)}"
+
+    def adc_to_ins(count):
+        return count / 32767.0 * 10.0
+
+    for i, truth_row in enumerate(truth):
+        for ch_idx, ch_name in enumerate(("Tran", "Vert", "Long")):
+            decoded_ips = adc_to_ins(ev.raw_samples[ch_name][i])
+            truth_ips   = truth_row[ch_idx]
+            # 0.003 in/s tolerance: <0.005 quantum + small float precision room
+            assert abs(decoded_ips - truth_ips) < 0.003, (
+                f"row {i} {ch_name}: decoded {decoded_ips:+.4f} vs "
+                f"truth {truth_ips:+.4f} (delta {decoded_ips - truth_ips:+.4f})"
+            )
+
+
 def test_save_imported_bw_with_paired_report(tmp_path: Path):
     """save_imported_bw + a paired BW ASCII report fold the report's
     rich derived fields into the sidecar.  This is the daemon-forwarded