fix(ltx): two-stage refine for Distilled 2.x T2V/I2V

auto_refine_upsample gated on supports_canonical_stage2 (Dev-only LoRA
path), so Distilled refine ran same-res for both stages and oversaturated.
Split the gate: supports_two_stage_refine covers any 2.x non-condition
variant and drives the staging plan plus UI Refine default;
supports_canonical_stage2 stays Dev-only for the LoRA branch.

modules/ltx/ltx_capabilities.py

@@ -37,6 +37,9 @@ class LTXCaps:
     modality_default_scale: float = 1.0
     guidance_rescale_default: float = 0.0
     supports_canonical_stage2: bool = False
+    # Stage 1 at target/2 -> 2x upsample -> Stage 2 at target. Distilled needs upsampled latents
+    # for refine; same-res refine oversaturates. Condition variants would need per-stage rebuild.
+    supports_two_stage_refine: bool = False
     stage2_dev_lora_repo: Optional[str] = None
 
 
@@ -121,6 +124,7 @@ def get_caps(model_name: str) -> Optional[LTXCaps]:
         elif variant == '2.0':
             caps.stage2_dev_lora_repo = 'CalamitousFelicitousness/LTX-2.0-distilled-lora-384-Diffusers'
     caps.supports_canonical_stage2 = caps.stage2_dev_lora_repo is not None
+    caps.supports_two_stage_refine = is_ltx2 and not is_condition_cls
 
     if is_ltx2:
         if variant == '2.3':

modules/ltx/ltx_process.py

@@ -174,13 +174,13 @@ def run_ltx(task_id,
             return
 
         # Lightricks TI2VidTwoStagesPipeline: Stage 1 at half-res, 2x upsample, Stage 2 refine at target.
-        # Auto-couple when the user picks Refine but not Upsample. Condition variants still need per-stage
-        # conditioning rebuild, so keep them on the same-resolution path.
+        # Auto-couple when the user picks Refine but not Upsample. Both Dev and Distilled refine paths
+        # expect upsampled latents; same-res refine on Distilled produces oversaturation. Condition
+        # variants still need per-stage conditioning rebuild and are excluded by supports_two_stage_refine.
         auto_refine_upsample = (
             refine_enable
-            and caps.supports_canonical_stage2
+            and caps.supports_two_stage_refine
             and not upsample_enable
-            and not caps.supports_multi_condition
         )
         effective_upsample_enable = upsample_enable or auto_refine_upsample
         effective_upsample_ratio = upsample_ratio if upsample_enable else 2.0

modules/ltx/ltx_ui.py

@@ -31,10 +31,10 @@ def _model_change(model_name: str):
         )
     # 2.x refine runs fixed canonical schedules; refine_strength only feeds 0.9.x LTXConditionPipeline.
     refine_strength_interactive = caps.family == '0.9'
-    # Default Refine on for Dev 2.x T2V/I2V: Lightricks' production recipe is Stage 1 + 2x upsample
-    # + Stage 2 refine (auto_refine_upsample at ltx_process.py:179 couples the stages once Refine is on).
-    # Multi-condition variants are excluded for the same reason auto_refine_upsample excludes them.
-    refine_default = caps.supports_canonical_stage2 and not caps.supports_multi_condition
+    # Default Refine on for any 2.x variant whose refine path expects upsampled latents (Dev and
+    # Distilled T2V/I2V). auto_refine_upsample at ltx_process.py:179 couples the stages once Refine
+    # is on. Condition variants are excluded by supports_two_stage_refine.
+    refine_default = caps.supports_two_stage_refine
     return (
         gr.update(visible=caps.supports_input_media),
         gr.update(visible=caps.supports_multi_condition),