refactor: revert replay code, preserve non-replay fixes

Revert raw IQ replay (commits 2cb56e8..6095893) to prepare
for unified SoftwareFPGA replay architecture.

Preserved: C-locale spinboxes, AGC chart label, demo/radar
mutual exclusion.

Delete v7/raw_iq_replay.py
Restore workers.py, processing.py, models.py, __init__.py, test_v7.py

9_Firmware/9_3_GUI/v7/__init__.py

@@ -11,7 +11,6 @@ top-level imports:
 from .models import (
     RadarTarget,
     RadarSettings,
-    WaveformConfig,
     GPSData,
     ProcessingConfig,
     TileServer,
@@ -67,7 +66,7 @@ except ImportError:  # PyQt6 not installed (e.g. CI headless runner)
 
 __all__ = [  # noqa: RUF022
     # models
-    "RadarTarget", "RadarSettings", "WaveformConfig", "GPSData", "ProcessingConfig", "TileServer",
+    "RadarTarget", "RadarSettings", "GPSData", "ProcessingConfig", "TileServer",
     "DARK_BG", "DARK_FG", "DARK_ACCENT", "DARK_HIGHLIGHT", "DARK_BORDER",
     "DARK_TEXT", "DARK_BUTTON", "DARK_BUTTON_HOVER",
     "DARK_TREEVIEW", "DARK_TREEVIEW_ALT",