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>

tools/genesis_laser_control.py

@@ -31,26 +31,19 @@ Date: 2026-01-24
 """
 
 import sys
-import time
-import struct
-from datetime import datetime
-from typing import Optional, List, Tuple
-from enum import IntEnum
 
-import serial
 from serial.tools import list_ports
 from PyQt6.QtWidgets import (
     QApplication, QMainWindow, QWidget, QVBoxLayout, QHBoxLayout,
     QTabWidget, QLabel, QSlider, QPushButton, QSpinBox, QCheckBox,
     QComboBox, QTextEdit, QLineEdit, QGroupBox, QGridLayout,
-    QMessageBox, QStatusBar, QProgressBar
+    QMessageBox, QStatusBar
 )
-from PyQt6.QtCore import Qt, QTimer, pyqtSignal, QSettings
-from PyQt6.QtGui import QFont, QPalette, QColor
+from PyQt6.QtCore import Qt, QTimer, QSettings
+from PyQt6.QtGui import QFont
 
 # Import core hardware control classes
 from hardware.genesis_core import (
-    I2CAddress, PCA9555Register, ControlBitmask,
     SerialComm, I2CProtocol, I2CDevices, LaserControl
 )