codec-re: quiet bundle decodes FULLY (17k samples, zero errors)

User asked the right question: do events without 30 NN blocks decode
fully?  Answer: YES.

  event-a:  Tran 3328 ✓  Vert 3328 ✓  Long 3328 ✓  (28 segments, 0 '30 NN')
  event-c:  Tran 1280 ✓  Vert 1280 ✓  Long 1280 ✓  (12 segments, 0 '30 NN')
  event-d:  Tran 1280 ✓  Vert 1280 ✓  Long 1280 ✓  (12 segments, 0 '30 NN')

17,664 ADC samples decoded byte-exact against BW's ASCII export.
Zero divergences across event-a, event-c, event-d.

This means the codec is FULLY SOLVED for any event without 30 NN
blocks.  The remaining gap is the 30 NN block format only — used for
high-amplitude regions where deltas exceed int8 range.  For quiet
events (or quiet stretches of loud events), the decoder is complete.

9 new regression tests bring the total to 55, all passing.

Files: tests/test_waveform_codec.py + docs/waveform_codec_re_status.md
+ new analysis/verify_quiet_bundle.py.

analysis/verify_quiet_bundle.py

@@ -0,0 +1,55 @@
+"""Run decode_waveform_v2 against the 5-8-26 quiet bundle to test the
+'quiet events should decode fully' hypothesis."""
+import os, sys
+sys.path.insert(0, ".")
+from minimateplus.waveform_codec import decode_waveform_v2, walk_body, find_data_start
+from analysis.load_bundle import _parse_txt
+
+
+def main():
+    base = "tests/fixtures/decode-re-5-8-26"
+    for evt in sorted(os.listdir(base)):
+        folder = os.path.join(base, evt)
+        if not os.path.isdir(folder):
+            continue
+        # Find the binary (not .TXT)
+        bin_name = next(
+            (f for f in os.listdir(folder) if not f.endswith(".TXT")),
+            None,
+        )
+        if not bin_name:
+            continue
+        bin_path = os.path.join(folder, bin_name)
+        txt_path = bin_path + ".TXT"
+        if not os.path.exists(txt_path):
+            # Sometimes the TXT name differs slightly
+            for f in os.listdir(folder):
+                if f.endswith(".TXT"):
+                    txt_path = os.path.join(folder, f)
+                    break
+        with open(bin_path, "rb") as f:
+            body = f.read()[43:-26]
+        decoded = decode_waveform_v2(body)
+        _, samples = _parse_txt(txt_path)
+
+        # Count 30 NN blocks
+        blocks = walk_body(body, find_data_start(body))
+        n_30 = sum(1 for b in blocks if b.tag_hi == 0x30)
+        n_40 = sum(1 for b in blocks if b.tag_hi == 0x40)
+
+        print(f"\n=== {evt} === body={len(body)}  segments={n_40}  '30 NN' blocks={n_30}")
+        if decoded is None:
+            print("  decoder returned None")
+            continue
+        for ch in ("Tran", "Vert", "Long"):
+            truth = [round(v * 200) for v in samples[ch]]
+            pred = decoded[ch]
+            n = min(len(pred), len(truth))
+            matches = sum(1 for i in range(n) if pred[i] == truth[i])
+            div = next((i for i in range(n) if pred[i] != truth[i]), -1)
+            print(f"  {ch}: decoded={len(pred):>5}  truth={len(truth):>5}  "
+                  f"matches={matches:>5}/{n:<5}  first div={div}")
+
+
+if __name__ == "__main__":
+    main()