feat(h5): standardize sensor-check into the .h5 (schema v2); SFM reads it

Make the sensor self-check a first-class part of the standardized decoded event
so SFM stops decoding it at report time — device-agnostic, per the store's
decoder→standardized-.h5→SFM model.

  * Event gains a `sensor_check` field; both decoders attach the traces where
    they set raw_samples — series-3 in event_file_io.read_blastware_file
    (minimateplus.sensor_check), series-4 in waveform_store's IDF path
    (micromate.sensor_check).  Covers ingest and backfill (both re-decode).
  * event_hdf5 bumps schema_version 1→2 and writes an optional /sensor_check
    group (raw counts, int32, per channel present).  read_event_hdf5 returns
    it; plot_json_from_hdf5 carries it as a top-level key.  Old v1 files still
    read cleanly (no group → None), so nothing breaks before the backfill.
  * gather_report_data reads sensor_check_waveforms from the .h5 and drops the
    report-time series-3 decode — the report no longer reaches into a decoder,
    and a series-4 event now lights up the same strip automatically.

Stored as raw counts (a shape diagnostic, rendered fit-to-box): the per-series
count scale differs and a physical mic unit is ill-defined, so conversion would
add complexity for no display benefit — easy to add later if a numeric use
appears.

Tests: .h5 roundtrip + backward-compat + plot_json + real series-3 decode
attaches to the Event.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YDXjZCr4RqT2U3QvMDhgzf

sfm/report_pdf.py

@@ -121,9 +121,11 @@ class ReportData:
     t0_ms:                  Optional[float] = None
     dt_ms:                  Optional[float] = None
 
-    # Sensor self-check traces — {ch: [samples]} in raw decode units, decoded
-    # from the binary's trailing block (see minimateplus.sensor_check). The
-    # little waveforms BW draws in its "Sensor Check" strip. Empty when absent.
+    # Sensor self-check traces — {ch: [samples]} in raw counts, read from the
+    # standardized .h5 (/sensor_check group, schema v2+) where the per-series
+    # decoder stored them at ingest.  The little diagnostic waveforms BW draws
+    # in its "Sensor Check" strip.  Empty when absent (pre-v2 .h5, histogram,
+    # or 3-channel unit's MicL).
     sensor_check_waveforms: dict = field(default_factory=dict)
 
     # Record-type discriminator
@@ -294,22 +296,15 @@ def gather_report_data(
             rd.pretrig_samples  = ta.get("pretrig_samples")
             rd.t0_ms            = ta.get("t0_ms")
             rd.dt_ms            = ta.get("dt_ms")
+            # Sensor self-check traces — read from the standardized .h5 (schema
+            # v2+).  Device-agnostic: whichever decoder produced the event
+            # stored them at ingest, so SFM reads them here without knowing or
+            # caring about the source instrument series.  Empty on pre-v2 files
+            # (until backfilled) and on 3-channel / histogram events.
+            rd.sensor_check_waveforms = wf.get("sensor_check") or {}
         except Exception as exc:
             log.warning("gather_report_data: hdf5 read failed: %s", exc)
 
-    # ── Sensor self-check traces — decoded from the retained raw binary ──
-    # The .h5 holds only the main waveform; the sensor-check traces live in the
-    # binary's trailing block, so decode them straight from the kept BW file.
-    # Waveform events only (histograms have no sensor-check strip).
-    if not rd.is_histogram:
-        try:
-            from minimateplus.sensor_check import decode_sensor_check
-            bw_path, _a5 = store.paths_for(serial, filename)
-            if bw_path.exists():
-                rd.sensor_check_waveforms = decode_sensor_check(bw_path.read_bytes())
-        except Exception as exc:
-            log.warning("gather_report_data: sensor-check decode failed: %s", exc)
-
     # ── Histogram aggregation ──
     # Codec emits ~N per-block samples (typically 1/sec); BW reports
     # one bar per configured interval (1 min / 5 min / etc.).  When