[refactor]: migrate examples/scripts to typed VideoGenerator API; rename api/compat.py to api/translation.py

Move all examples/inference and scripts off the legacy
VideoGenerator.from_pretrained(model, **kwargs) +
generate_video(prompt, **kwargs) surface onto the typed
from_config(GeneratorConfig(...)) + generate(GenerationRequest(...))
convention, including the Kandinsky-5 and DreamX-World examples added
on main after the original migration. git-mv api/compat.py to
api/translation.py ('compat' implied a temporary shim; the forward
translation is its honest permanent role) and repoint all importers,
tests, and doc links.

examples/inference/basic/basic_stable_audio.py

@@ -51,25 +51,31 @@ Prerequisites:
          uv pip install k_diffusion einops_exts alias_free_torch torchsde
 """
 from fastvideo import VideoGenerator
+from fastvideo.api import (EngineConfig, GenerationRequest, GeneratorConfig,
+                           OutputConfig)
 
 PROMPT = "Lo-fi hip hop instrumental with vinyl crackle and gentle piano."
 
 
 def main() -> None:
-    generator = VideoGenerator.from_pretrained(
-        "FastVideo/stable-audio-open-1.0-Diffusers",
-        num_gpus=1,
-    )
+    generator = VideoGenerator.from_config(
+        GeneratorConfig(
+            model_path="FastVideo/stable-audio-open-1.0-Diffusers",
+            engine=EngineConfig(num_gpus=1),
+        ))
     output_path = "outputs_audio/stable_audio_basic/output_stable_audio.wav"
-    generator.generate_video(
-        prompt=PROMPT,
-        output_path=output_path,
-        save_video=True,
-        # 6-second clip; the model max is ~47.5s.
-        audio_end_in_s=6.0,
-        # The registered preset gives 100 steps + CFG=7.0 by default;
-        # override num_inference_steps / guidance_scale here for QA.
-    )
+    generator.generate(
+        GenerationRequest(
+            prompt=PROMPT,
+            output=OutputConfig(
+                output_path=output_path,
+                save_video=True,
+            ),
+            # 6-second clip; the model max is ~47.5s.
+            extensions={"audio_end_in_s": 6.0},
+            # The registered preset gives 100 steps + CFG=7.0 by default;
+            # override num_inference_steps / guidance_scale here for QA.
+        ))
     generator.shutdown()