fix(examples): camera-python-effects's processors take a config class instead of keyword parameters

[tato123]

What & why

examples/camera-python-effects's processors still take their configuration as keyword parameters on __init__. Since v0.21.0 (#2226), @processor refuses that signature at decoration, so importing the processor module raises and the example no longer starts.

This is the consumer backlog the agent-readable-processor-catalog change owes at ship (docs/plan/changes/archive/2026-09-13-agent-readable-processor-catalog.md). Per docs/plan/ARCHITECTURE.md §Consumers, a converted consumer's breakage is filed at that consumer and never blocks the engine change.

Design

Each processor below takes one config parameter annotated with a config class, and reads its values off that object. The config class is a dataclass whose fields are today's keyword parameters with their defaults, or a TypedDict. rt.add(..., config={...}) in the app stays as it is: the helper builds the config class from the dict. examples/camera-virtual-camera/processors/shader_effect.py (ShaderEffectConfig) is the in-tree model.

• examples/camera-python-effects/src/camera_python_effects/processors/crt_film_grain.py — CrtFilmGrain(barrel_curve, scanline_intensity, chromatic_aberration, grain_intensity, grain_speed, vignette_intensity, brightness)
• examples/camera-python-effects/src/camera_python_effects/processors/cyberpunk_avatar.py — CyberpunkAvatar(scene_width, scene_height, detection_confidence, pose_model_path)
• examples/camera-python-effects/src/camera_python_effects/processors/lerobot_recorder.py — LeRobotRecorder(dataset_root, repo_id, fps, episode_seconds, task, record_stylized) (dataset_root is required, so its field has no default)
• examples/camera-python-effects/src/camera_python_effects/processors/neon_overlay_source.py — NeonOverlaySource(width, height)

Done means

• Every processor above declares def __init__(self, config: <ConfigClass>), and no @processor class in the example takes a keyword parameter.
• The example starts against the published wheel and reaches a running graph.

Validation shape

A fresh uv sync in the example, then run it as its README says. The processor modules import without a decoration refusal and the graph reaches Running.

Needs the physical rig?

GPU, camera

Non-derivable notes

Examples pin the published wheel, so validation needs a release carrying #2226 and #2228 (v0.22.0 or later). A local maturin develop is undone by uv sync.