feat(import): parse paired BW ASCII reports on /db/import/blastware_file

Blastware's ACH writes a per-event ASCII report (.TXT) alongside each
event binary, containing the rich derived per-channel fields BW
computes (PPV, ZC Freq, Time of Peak, Peak Acceleration, Peak
Displacement, Peak Vector Sum + time, sensor self-check Pass/Fail,
monitor-log timestamps).  None of this lives in the BW binary itself.

When the watcher daemon forwards both files to /db/import/blastware_file
in one multipart POST, we now:

  - Pair binaries with their .TXT partners by filename match
  - Parse the report into a structured BwAsciiReport
  - Land the rich fields in a new top-level `bw_report` block of the
    sidecar JSON
  - Overlay the report's peaks/project_info/timestamp/sample_rate/
    record_time/total_samples/pretrig_samples onto the canonical
    sidecar fields (the report values are device-authoritative; the
    BW-binary STRT-derived values had bugs like reading the 0x46
    record-type marker as rectime)

This unblocks the monthly-summary review workflow — events become
sortable/filterable by peak, location, project, etc. — without
depending on the still-undecoded waveform body codec.

sfm/server.py

@@ -1619,6 +1619,21 @@ async def db_import_blastware_file(
          writes a .sfm.json sidecar with source.kind = "bw-import".
       2. Upsert a row into `events` (dedup'd on serial+timestamp).
 
+    **Paired BW ASCII reports.**  When Blastware's ACH writes events,
+    it also emits a per-event report alongside each binary as
+    ``<binary>.TXT`` (e.g. ``M529LK44.AB0`` + ``M529LK44.AB0.TXT``).
+    If a request includes ``.TXT`` files matching a binary's filename,
+    the report is parsed and its decoded fields land in the sidecar's
+    ``bw_report`` block — including device-authoritative peaks, ZC
+    Freq, Peak Acceleration, Peak Displacement, Time of Peak, sensor
+    self-check results, and monitor-log timestamps.  The daemon-
+    forwarded ACH workflow should always send both files together
+    so the SFM database has the rich metadata for sort/filter/report.
+
+    Pairing is by exact filename match (case-insensitive on the
+    extension): a binary named ``foo.AB0`` is paired with a report
+    named ``foo.AB0.TXT`` or ``foo.AB0.txt``.
+
     Response includes per-file outcomes so the caller can see which
     landed cleanly and which failed (e.g. malformed file, unknown
     serial, etc.).
@@ -1627,21 +1642,36 @@ async def db_import_blastware_file(
     db    = _get_db()
     results: list[dict] = []
 
+    # Read every upload up front (UploadFile.read() is one-shot under
+    # FastAPI's spooled-tempfile backing) and split into binaries vs
+    # paired ASCII reports.
+    binaries: list[tuple[str, bytes]] = []
+    reports:  dict[str, bytes]        = {}   # keyed by lower-cased stem (without .txt)
     for upload in files:
+        name = upload.filename or ""
         try:
             content = await upload.read()
         except Exception as exc:
             results.append({
-                "filename": upload.filename, "status": "error",
-                "detail": f"read failed: {exc}",
+                "filename": name or "<unnamed>", "status": "error",
+                "detail":   f"read failed: {exc}",
             })
             continue
 
+        if name.lower().endswith(".txt"):
+            # Strip the ".txt" suffix to get the binary's filename.
+            reports[name[:-4].lower()] = content
+        else:
+            binaries.append((name, content))
+
+    for filename, content in binaries:
+        report_bytes = reports.get(filename.lower())
         try:
             ev, rec = store.save_imported_bw(
                 content,
-                source_path=Path(upload.filename or "imported.bw"),
+                source_path=Path(filename or "imported.bw"),
                 serial_hint=serial,
+                bw_report_text=report_bytes,
             )
             inserted, skipped = db.insert_events(
                 [ev],
@@ -1652,21 +1682,31 @@ async def db_import_blastware_file(
                 } if ev._waveform_key else None,
             )
             results.append({
-                "filename":         upload.filename,
+                "filename":         filename,
                 "status":           "ok",
                 "stored_filename":  rec["filename"],
                 "filesize":         rec["filesize"],
                 "sha256":           rec["sha256"],
+                "report_attached":  report_bytes is not None,
                 "inserted":         inserted,
                 "skipped":          skipped,
             })
         except Exception as exc:
-            log.error("import failed for %s: %s", upload.filename, exc, exc_info=True)
+            log.error("import failed for %s: %s", filename, exc, exc_info=True)
             results.append({
-                "filename": upload.filename, "status": "error",
+                "filename": filename, "status": "error",
                 "detail":   str(exc),
             })
 
+    # Surface unmatched .txt uploads so the daemon can detect mis-pairings.
+    used_report_keys = {fn.lower() for fn, _ in binaries}
+    for stem in reports.keys() - used_report_keys:
+        results.append({
+            "filename":  stem + ".txt",
+            "status":    "warning",
+            "detail":    "BW ASCII report supplied but no matching binary in this upload",
+        })
+
     return {"count": len(results), "results": results}