flatudp: vector rows as channels or as a waveform, a re-openable source, probes for both

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tools/mock_flatudp.py

@@ -7,7 +7,9 @@ One datagram is one cycle: the signals concatenated in declaration order, no pad
 chosen byte order. Packet i carries, for the signal of index k (from 0) and its element e,
 the value (i * (k + 1) + e) % 100, so consecutive datagrams are predictable.
 
-  --signals     name:type[count],...   default Trigger:uint8,Ia:float32,Cnt:uint64,Wave:int16[4]
+  --signals     name:type[count][w],...   default Trigger:uint8,Ia:float32,Cnt:uint64,Wave:int16[4]
+                (the datagram is the same with or without the app's trailing w, which only says
+                how the app shows a vector: one channel per element, or one waveform channel)
   --rate        cycles per second
   --big-endian  pack big endian (default little)
   --gap S,D     send nothing from S to S+D seconds after the start (a sender that stops)
@@ -32,7 +34,7 @@ def parse_signals(text):
         count = 1
         if "[" in ty:
             ty, _, n = ty.partition("[")
-            count = int(n.rstrip("]"))
+            count = int(n.strip().rstrip("w").rstrip().rstrip("]"))  # a trailing w (waveform) is the app's
         out.append((name.strip(), CODES[ty.strip()], count))
     return out