Add H3 latent upscale refinement stage

H3_LONG_VIDEOS_GUIDE.md

@@ -1149,81 +1149,34 @@ These two belong together.
 
 If you change `shift_video`, you usually need to change `shift_audio` in proportion.
 
-## Group 8: Detail Pass
+## Group 8: Latent Upscale
 
-This is the optional second pass.
+This is the optional latent refinement stage, used before decode.
 
-### `detail_pass`
-
-Enables the refinement pass.
+The long-video node now expects a separate `Dumas H3 Latent Upscale Params` node for this stage.
+Wire that node into the `latent_upscale_param` input when you want the shot to be upscaled and lightly
+re-sampled before decode.
 
 What this really means:
 
 - the node renders the beat once
-- then runs a second sampler pass over that result
-- the goal is to polish, not to invent a whole different shot
-
-### `detail_sampler_name`
-
-Sampler for the refinement pass.
-
-### `detail_scheduler`
-
-Scheduler for the refinement pass.
-
-### `detail_steps`
-
-Extra steps for the refinement pass.
-
-What this really means:
-
-- more steps gives the second pass more opportunity to change the image
-- that can help detail
-- but after a point it stops being "cleanup" and starts becoming "rewrite"
-
-### `detail_denoise`
-
-How strongly the refinement pass is allowed to rewrite the beat.
-
-What this really means:
-
-- low denoise = polish what is already there
-- high denoise = let the second pass substantially alter what is already there
-
-### How The Detail-Pass Settings Work Together
-
-The detail pass starts from the first-pass result and tries to polish it.
-
-Gentle settings:
-
-- low to medium `detail_steps`
-- low `detail_denoise`
-
-Aggressive settings:
-
-- high `detail_steps`
-- high `detail_denoise`
-
-Aggressive settings can improve texture, but they can also:
-
-- change faces
-- pull away from references
-- break continuity
-
-That is why this group should be read as one combined strength control:
-
-- `detail_pass` decides whether the second pass exists
-- `detail_steps` decides how long it keeps working
-- `detail_denoise` decides how free it is to change things
-- `detail_sampler_name` and `detail_scheduler` shape how that rewrite behaves
+- the sampled latent is upscaled in latent space to the target size
+- the conditioning is rebuilt at that target size
+- the node then runs a hard-coded 2-step refinement pass over the upscaled latent
 
 Good starting point:
 
-- `detail_pass = on`
-- `detail_sampler_name = euler`
-- `detail_scheduler = beta`
-- `detail_steps = 4` to `8`
-- `detail_denoise = 0.20` to `0.35`
+- use the `model` mode when you want the strongest latent detail recovery
+- use the interpolation mode when you want a cheaper resize-only path
+- keep the refinement denoise low to medium
+
+The important part is that this stage is still a latent pass, not a pixel-space resize:
+
+- it happens before decode
+- it can change structure more than a normal image upscale
+- it is the place to recover detail without adding another full detail-pass toggle
+
+If you do not wire the helper node, the long-video node skips latent upscale entirely and renders as before.
 
 ## Group 9: Performance, Decode, And Upscale