feat: add SEARCH_ALIASES for model and misc nodes

Add search aliases to model-related and miscellaneous nodes:
- Model nodes: nodes_model_merging.py, nodes_model_advanced.py, nodes_lora_extract.py
- Sampler nodes: nodes_custom_sampler.py, nodes_align_your_steps.py
- Control nodes: nodes_controlnet.py, nodes_attention_multiply.py, nodes_hooks.py
- Training nodes: nodes_train.py, nodes_dataset.py
- Utility nodes: nodes_logic.py, nodes_canny.py, nodes_differential_diffusion.py
- Architecture-specific: nodes_sd3.py, nodes_pixart.py, nodes_lumina2.py, nodes_kandinsky5.py, nodes_hidream.py, nodes_fresca.py, nodes_hunyuan3d.py
- Media nodes: nodes_load_3d.py, nodes_webcam.py, nodes_preview_any.py, nodes_wanmove.py

Uses search_aliases parameter in io.Schema() for v3 nodes, SEARCH_ALIASES class attribute for legacy nodes.

comfy_extras/nodes_differential_diffusion.py

@@ -11,6 +11,7 @@ class DifferentialDiffusion(io.ComfyNode):
     def define_schema(cls):
         return io.Schema(
             node_id="DifferentialDiffusion",
+            search_aliases=["inpaint gradient", "variable denoise strength"],
             display_name="Differential Diffusion",
             category="_for_testing",
             inputs=[