feat(protocol): fully decode Blastware filename encoding and update related documentation

sfm/server.py

@@ -858,15 +858,22 @@ def device_event_blastware_file(
     tcp_port: int           = Query(DEFAULT_TCP_PORT, description=f"TCP port (default {DEFAULT_TCP_PORT})"),
 ) -> FileResponse:
     """
-    Download the full waveform for a single event (0-based index) and return it
-    as a Blastware-compatible binary file (.N00 for single-shot, .9T0 for continuous).
+    Download the waveform for a single event (0-based index) and return it
+    as a Blastware-compatible binary file with a correct Blastware filename.
 
     Supply either *port* (serial) or *host* (TCP/modem).
 
-    The file is written to a temporary path under /tmp and streamed back as a
-    file download.  Blastware can open it directly.
+    The file is written to /tmp and streamed back as a binary download.
+    Blastware can open it directly — filename encodes serial + timestamp.
 
-    Performs: POLL startup → get_events(full_waveform=True, stop_after_index=index)
+    Filename format: <prefix><serial3><stem><AB>0<W|H>
+      - prefix letter = chr(ord('B') + floor(serial_numeric / 1000))
+      - stem + AB     = second-resolution timestamp since 1985-01-01 local
+      - W / H         = Full Waveform / Full Histogram (defaults to W for
+                        triggered events; histogram requires recording_mode
+                        to be populated from compliance config)
+
+    Performs: POLL startup → get_events(full_waveform=False, stop_after_index=index)
     → write_n00() → FileResponse.
     """
     log.info(
@@ -879,7 +886,7 @@ def device_event_blastware_file(
             with _build_client(port, baud, host, tcp_port, timeout=120.0) as client:
                 info = client.connect()
                 # Use full_waveform=False (metadata-only, stop_after_metadata=True) —
-                # Blastware writes .N00 files from only the first ~8 A5 frames, NOT
+                # Blastware writes waveform files from only the first ~8 A5 frames, NOT
                 # the full bulk download.  Using full_waveform=True produces a file
                 # ~8x larger than Blastware's because it includes all post-event
                 # silence chunks.  The metadata-only a5_frames (with terminator) are