Polymorphism Phase 2 + remove unused gamma/saturation fields

ProcessorManager: replace all isinstance checks with property-based
dispatch via base TargetProcessor (device_id, led_client,
get_display_index, update_device, update_calibration).

Remove gamma/saturation from ProcessingSettings, ColorCorrection
schema, serialization, and migration — these were never used in the
processing pipeline and are handled by postprocessing template filters.
Delete dead apply_color_correction() function.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/core/capture/pixel_processor.py

@@ -8,56 +8,6 @@ from wled_controller.utils import get_logger
 logger = get_logger(__name__)
 
 
-def apply_color_correction(
-    colors: List[Tuple[int, int, int]],
-    gamma: float = 2.2,
-    saturation: float = 1.0,
-    brightness: float = 1.0,
-) -> List[Tuple[int, int, int]]:
-    """Apply color correction to LED colors.
-
-    Args:
-        colors: List of (R, G, B) tuples
-        gamma: Gamma correction factor (default 2.2)
-        saturation: Saturation multiplier (0.0-2.0)
-        brightness: Brightness multiplier (0.0-1.0)
-
-    Returns:
-        Corrected list of (R, G, B) tuples
-    """
-    if not colors:
-        return colors
-
-    # Convert to numpy array for efficient processing
-    colors_array = np.array(colors, dtype=np.float32) / 255.0
-
-    # Apply brightness
-    if brightness != 1.0:
-        colors_array *= brightness
-
-    # Apply saturation
-    if saturation != 1.0:
-        # Convert RGB to HSV-like saturation adjustment
-        # Calculate luminance (grayscale)
-        luminance = np.dot(colors_array, [0.299, 0.587, 0.114])
-        luminance = luminance[:, np.newaxis]  # Reshape for broadcasting
-
-        # Blend between grayscale and color based on saturation
-        colors_array = luminance + (colors_array - luminance) * saturation
-
-    # Apply gamma correction
-    if gamma != 1.0:
-        colors_array = np.power(colors_array, 1.0 / gamma)
-
-    # Clamp to valid range and convert back to integers
-    colors_array = np.clip(colors_array * 255.0, 0, 255).astype(np.uint8)
-
-    # Convert back to list of tuples
-    corrected_colors = [tuple(color) for color in colors_array]
-
-    return corrected_colors
-
-
 def smooth_colors(
     current_colors: List[Tuple[int, int, int]],
     previous_colors: List[Tuple[int, int, int]],