[refactor]: move repository configs and examples off pipeline.experimental

Every key that repository YAML configs, Python examples, the Dreamverse
backend, and tests passed through pipeline.experimental has a typed
GeneratorConfig field, so they use those fields instead:
engine.attention, engine.compile.regional, pipeline.flow_shift,
pipeline.embedded_cfg_scale, pipeline.dmd_denoising_steps,
pipeline.components.lora_nickname, pipeline.minimax_h3, and
pipeline.longcat. No repository config outside the tests uses
pipeline.experimental any more.

The flat FastVideoArgs keywords that each migrated YAML file and each
basic_fasth3.py option set produces match the previous ones. The golden
snapshots of the two Hunyuan scripts now record embedded_cfg_scale and
flow_shift as floats (6.0 instead of 6), because the typed fields are
floats. The guidance tensor is built as float32 either way. The golden case
untyped_experimental_keys is renamed attention_precision_and_flow_shift with
identical content, and keys_without_typed_fields covers keywords that still
go to pipeline.experimental.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012M91wnVFmPEvJ9h39r5BH7

examples/inference/basic/basic_dmd_new_api.py

@@ -3,12 +3,12 @@ import time
 
 from fastvideo import VideoGenerator
 from fastvideo.api import (
+    AttentionConfig,
     EngineConfig,
     GenerationRequest,
     GeneratorConfig,
     OffloadConfig,
     OutputConfig,
-    PipelineSelection,
 )
 
 OUTPUT_PATH = "video_samples_dmd2_typed"
@@ -29,12 +29,8 @@ def main():
                 dit=False,
                 vae=False,
             ),
+            attention=AttentionConfig(vsa_sparsity=0.8),
         ),
-        # PR 2 still routes a few advanced inference knobs through the
-        # compatibility bridge until they get first-class typed fields.
-        pipeline=PipelineSelection(experimental={
-            "VSA_sparsity": 0.8,
-        }, ),
     )
 
     load_start_time = time.perf_counter()