Phase 1c: prune remaining dead functions, unused imports, quarantine Genesis

- uc480_camera: drop never-called _capture_paused/get_framerate (the
  hardware question _capture_paused encoded is now in KNOWN_ISSUES.md)
- t3r_protocol: drop read_reg/write_reg/decode_reg/Reg (commands never
  wired into the driver)
- bbd20x: drop _update0x0212 (never dispatched) and 8 of 9 unused
  trigger convenience wrappers; apt_constants: drop TriggerBitsStepper
  (servo-only rig)
- ruff --fix: 35 unused imports across all apps; drop unused T3R_BAUD
- genesis_core.py: quarantine warning header; docs/genesis_verification.md
  bench checklist for the 7 divergences vs tools/genesis_laser_gui.py

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

hardware/uc480_camera.py

@@ -14,7 +14,6 @@ from PyQt6.QtCore import QThread, pyqtSignal, QObject
 from PyQt6.QtGui import QImage
 import logging
 import threading
-from contextlib import contextmanager
 from typing import List, Optional, Tuple
 
 logger = logging.getLogger(__name__)
@@ -331,29 +330,6 @@ class UC480Camera(QObject):
         logger.info("Video capture stopped")
         return True
 
-    @contextmanager
-    def _capture_paused(self):
-        """
-        Context manager that temporarily stops live video while a camera
-        parameter is being changed, then restarts it.  Many IDS cameras
-        return IS_CANT_COMMUNICATE_WITH_DRIVER (17) or IS_NO_SUCCESS (-1)
-        when gain/exposure commands are issued during active capture.
-        """
-        with self._settings_lock:
-            was_capturing = self.is_capturing
-            if was_capturing:
-                ueye.is_StopLiveVideo(self.h_cam, ueye.IS_WAIT)
-                self.is_capturing = False
-            try:
-                yield
-            finally:
-                if was_capturing:
-                    ret = ueye.is_CaptureVideo(self.h_cam, ueye.IS_DONT_WAIT)
-                    if ret == ueye.IS_SUCCESS:
-                        self.is_capturing = True
-                    else:
-                        logger.error(f"Failed to restart capture after settings change: {ret}")
-
     def get_frame(self) -> Optional[QImage]:
         """
         Capture a single frame from the camera.
@@ -535,24 +511,6 @@ class UC480Camera(QObject):
             logger.error(f"Failed to set framerate: {ret}")
             return False
 
-    def get_framerate(self) -> Optional[float]:
-        """
-        Get current framerate.
-
-        Returns:
-            Framerate in fps, or None if failed
-        """
-        if not self.is_initialized:
-            return None
-
-        fps = ueye.c_double()
-        ret = ueye.is_GetFramesPerSecond(self.h_cam, fps)
-
-        if ret == ueye.IS_SUCCESS:
-            return fps.value
-        else:
-            return None
-
     def set_gain(self, master_gain: int) -> bool:
         """
         Set camera master gain.