feat: add Flux2 support — CLIP type, model sampling, and override

- Add "flux2" to clip_types and dual_clip_types lists so CLIPType.FLUX2
  is correctly passed to ComfyUI's text encoder loader
- Add "flux2" model_sampling_override option in Builder UI dropdown
- Implement ModelSamplingFlux2 handler using fixed shift (default 2.02,
  matching ComfyUI's Flux2 supported_models.py)
- Handle "flux2" in config_builder_node.py config generation with
  default shift value

Users with Flux2 models (Klein, etc.) should set:
- CLIP Type: flux2
- Model Sampling Override: Flux2
- For best results: enable Advanced Sampling with Flux2 Scheduler

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

config_builder_node.py

@@ -644,6 +644,8 @@ class UltimateConfigBuilder:
                 if model_sampling_override == "flux":
                     config["model_sampling_flux_max_shift"] = model_sampling_flux_max_shift
                     config["model_sampling_flux_base_shift"] = model_sampling_flux_base_shift
+                elif model_sampling_override == "flux2":
+                    config["model_sampling_shift"] = model_sampling_shift if model_sampling_shift else "2.02"
                 else:
                     config["model_sampling_shift"] = model_sampling_shift
             config["use_advanced_sampling"] = use_advanced_sampling or False
@@ -1057,10 +1059,10 @@ async def get_model_lists_endpoint(request):
         clip_types = [
             "stable_diffusion", "stable_cascade", "sd3", "stable_audio",
             "mochi", "ltxv", "pixart", "cosmos", "lumina2", "wan",
-            "hidream", "chroma", "ace", "flux"
+            "hidream", "chroma", "ace", "flux", "flux2"
         ]
         dual_clip_types = [
-            "sdxl", "sd3", "flux", "hunyuan_video", "hidream",
+            "sdxl", "sd3", "flux", "flux2", "hunyuan_video", "hidream",
             "hunyuan_image", "hunyuan_video_15"
         ]
 

image_generation.py

@@ -129,6 +129,18 @@ def generate_image(
             patched_model.add_object_patch("model_sampling", model_sampling)
             print(f"[GridTester] 🔧 Applied ModelSamplingFlux (max_shift={max_s}, base_shift={base_s}, computed_shift={shift:.4f})")
 
+        elif model_sampling_override == "flux2":
+            # Flux2: uses ModelSamplingFlux with fixed shift (default 2.02, matching ComfyUI's Flux2 supported_models)
+            sampling_base = comfy.model_sampling.ModelSamplingFlux
+            sampling_type = comfy.model_sampling.CONST
+            class ModelSamplingAdvanced(sampling_base, sampling_type):
+                pass
+            shift = float(model_sampling_shift) if model_sampling_shift else 2.02
+            model_sampling = ModelSamplingAdvanced(patched_model.model.model_config)
+            model_sampling.set_parameters(shift=shift)
+            patched_model.add_object_patch("model_sampling", model_sampling)
+            print(f"[GridTester] 🔧 Applied ModelSamplingFlux2 (shift={shift})")
+
     # === Flux Guidance ===
     # Modify positive conditioning with guidance value (used by Flux 1 models)
     if flux_guidance_value and float(flux_guidance_value) > 0: