fix(gui): PR-Q.4 — per-subframe WaveformConfig + 48-bin parser (C-5)

Refactor v7.WaveformConfig from single-PRI to PR-Q's 3-PRI staggered
ladder (SHORT 175 us / MEDIUM 161 us / LONG 167 us) and update the
host-side bulk-frame parser dimension to match the FPGA's 48-bin
Doppler output (RP_NUM_DOPPLER_BINS = 48). The parser was rejecting
every production frame with n_doppler != 32, masking the PR-F widening
end-to-end.

WaveformConfig:
- pri_short_s/pri_medium_s/pri_long_s replace single pri_s
- n_doppler_bins 32 -> 48; new num_subframes=3
- Per-subframe velocity_resolution_{short,medium,long}_mps
- Per-subframe max_velocity_{short,medium,long}_mps
- extended_max_velocity_mps_crt(K=6) for 3-PRI alias-resolution ceiling
- Drop pri_s, velocity_resolution_mps, max_velocity_mps (no aliases)

Other:
- radar_protocol.NUM_DOPPLER_BINS 32 -> 48 (NUM_CELLS auto 16384 -> 24576;
  BULK_FRAME_MAX_SIZE flows from NUM_CELLS, no other edits needed)
- v7/dashboard.py constant + stale "(64x32)" title replaced with f-string
- v7/processing.py 32-bin fallback -> 48
- v7/workers.py: derive doppler_center from frame.shape; LONG-PRI v_res
  used as conservative single-PRI placeholder until PR-Q.5 lands the
  CRT extractor (markers in place at both call sites)
- test_v7.py: TestWaveformConfig rewritten (8 tests, per-subframe + CRT
  extension); TestExtractTargetsFromFrame center 16 -> 24

Local tests:
  TestWaveformConfig            8/8 PASS
  TestExtractTargetsFromFrame   6/6 PASS
  test_GUI_V65_Tk             117/0/2 PASS

9_Firmware/9_3_GUI/v7/processing.py

@@ -516,7 +516,7 @@ def extract_targets_from_frame(
         One target per detection cell.
     """
     det_indices = np.argwhere(frame.detections > 0)
-    n_doppler = frame.detections.shape[1] if frame.detections.ndim == 2 else 32
+    n_doppler = frame.detections.shape[1] if frame.detections.ndim == 2 else 48
     doppler_center = n_doppler // 2
 
     targets: list[RadarTarget] = []