feat: preserve and encode raw 0C record in sidecar extensions for offline analysis

tests/test_event_file_io.py

@@ -127,6 +127,59 @@ def test_sidecar_write_and_read_round_trip(tmp_path: Path):
     assert loaded["source"]["kind"] == "sfm-ach"
 
 
+def test_sidecar_persists_raw_0c_record_in_extensions(tmp_path: Path):
+    """An Event with _raw_record populated should land its 210 bytes
+    base64-encoded in extensions.raw_records.waveform_record_b64, so
+    later analysis (e.g. mapping Peak Acceleration / Time of Peak / ZC
+    Freq byte offsets) can run offline against the saved sidecar."""
+    import base64
+
+    ev, _ = _make_synthetic_event()
+    # Synthesize a 210-byte 0C record with embedded label needles so
+    # the dump tool's anchor scan has something to find.
+    raw = bytearray(210)
+    raw[10:14]   = b"Tran"
+    raw[60:64]   = b"Vert"
+    raw[110:114] = b"Long"
+    raw[160:164] = b"MicL"
+    ev._raw_record = bytes(raw)
+
+    d = event_file_io.event_to_sidecar_dict(
+        ev, serial="BE11529",
+        blastware_filename="M529LKIQ.7M0W", blastware_filesize=1024,
+        blastware_sha256="x" * 64, source_kind="sfm-live",
+    )
+
+    rr = d["extensions"]["raw_records"]
+    assert rr["waveform_record_len"] == 210
+    decoded = base64.b64decode(rr["waveform_record_b64"])
+    assert decoded == ev._raw_record
+
+    # Round-trip through write/read
+    path = tmp_path / "raw0c.sfm.json"
+    event_file_io.write_sidecar(path, d)
+    loaded = event_file_io.read_sidecar(path)
+    assert (
+        base64.b64decode(loaded["extensions"]["raw_records"]["waveform_record_b64"])
+        == ev._raw_record
+    )
+
+
+def test_sidecar_omits_raw_records_when_event_has_no_0c(tmp_path: Path):
+    """Events without a _raw_record (e.g. constructed by importers that
+    never see 0C) should NOT add an empty raw_records block — keep the
+    sidecar clean for those flows."""
+    ev, _ = _make_synthetic_event()
+    assert ev._raw_record is None
+
+    d = event_file_io.event_to_sidecar_dict(
+        ev, serial="BE11529",
+        blastware_filename="M529LKIQ.7M0W", blastware_filesize=1024,
+        blastware_sha256="x" * 64, source_kind="bw-import",
+    )
+    assert d["extensions"] == {}
+
+
 def test_sidecar_rejects_unsupported_schema_version(tmp_path: Path):
     path = tmp_path / "future.sfm.json"
     path.write_text(json.dumps({