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/radar_protocol.py

@@ -68,8 +68,8 @@ DATA_PACKET_SIZE = 11               # 1 + 4 + 2 + 2 + 1 + 1
 STATUS_PACKET_SIZE = 26              # 1 + 24 + 1
 
 NUM_RANGE_BINS = 512
-NUM_DOPPLER_BINS = 32
-NUM_CELLS = NUM_RANGE_BINS * NUM_DOPPLER_BINS  # 16384
+NUM_DOPPLER_BINS = 48                 # PR-F/PR-Q: 3 sub-frames * 16 (matches FPGA RP_NUM_DOPPLER_BINS)
+NUM_CELLS = NUM_RANGE_BINS * NUM_DOPPLER_BINS  # 24576
 
 WATERFALL_DEPTH = 64