feat: add essential subgraph blueprints

Add 24 non-cloud essential blueprints from comfyui-wiki/Subgraph-Blueprints.
These cover common workflows: text/image/video generation, editing,
inpainting, outpainting, upscaling, depth maps, pose, captioning, and more.

Cloud-only blueprints (5) are excluded and will be added once
client-side distribution filtering lands.

Amp-Thread-ID: https://ampcode.com/threads/T-019c6f43-6212-7308-bea6-bfc35a486cbf

comfy_extras/nodes_post_processing.py

@@ -19,6 +19,7 @@ class Blend(io.ComfyNode):
     def define_schema(cls):
         return io.Schema(
             node_id="ImageBlend",
+            display_name="Image Blend",
             category="image/postprocessing",
             inputs=[
                 io.Image.Input("image1"),
@@ -76,6 +77,7 @@ class Blur(io.ComfyNode):
     def define_schema(cls):
         return io.Schema(
             node_id="ImageBlur",
+            display_name="Image Blur",
             category="image/postprocessing",
             essentials_category="Image Tools",
             inputs=[