Implement BiRefNet and HAT Sharper models with background removal capabilities

- Added validation documentation for AI model tiers.
- Introduced `background.py` for background removal logic, including inference functions for alpha and foreground extraction.
- Created `onnx_birefnet.py` to handle BiRefNet model sessions and alpha inference.
- Developed tests for background models, ensuring proper dispatch and session reuse.
- Added tests for BiRefNet ONNX model to validate alpha output and error handling for invalid values.
- Implemented model export scripts for BiRefNet and HAT Sharper, ensuring proper weight compression and licensing.
- Created `deform_sampling.py` for deformable convolution operations used in BiRefNet.
- Added utility functions for compressing ONNX weights without altering graph arithmetic.
- Introduced a reference plane node for depth field adjustments in geometry processing.

tools/models/cli.py

@@ -63,18 +63,13 @@ MODEL_BUILDS = {
         ),
         exporter="realesrgan_wdn_x4",
     ),
-    "SAFMN_REAL_X4": BuildSpec(
-        source_url=(
-            "https://github.com/sunny2109/SAFMN/releases/download/"
-            "v0.1.0/SAFMN_L_Real_LSDIR_x4-v2.pth"
-        ),
-        source_filename="SAFMN_L_Real_LSDIR_x4-v2.pth",
-        source_size=45002097,
-        source_sha256=(
-            "f1ac0ee3ee143fbbc49aff6584cb7b48b71ba8d1961dfb8ad076b98ca4799ae2"
-        ),
-        exporter="safmn_real_x4",
-    ),
+}
+
+ISOLATED_EXPORTERS = {
+    "MOGE3_VITL": ("moge3_export.py", ()),
+    "HAT_GAN_X4_SHARPER": ("hat_export.py", ()),
+    "BIREFNET_LITE": ("birefnet_export.py", ("--variant", "lite")),
+    "BIREFNET_HR_MATTING": ("birefnet_export.py", ("--variant", "hr-matting")),
 }
 
 
@@ -194,21 +189,24 @@ def prepare_model(model):
     if model.build:
         build_model(model)
         return
-    if model.key in {"PISA_SR", "MOGE3_VITL"}:
+    if model.key in ISOLATED_EXPORTERS:
         model.destination.parent.mkdir(parents=True, exist_ok=True)
-        exporter = "pisa_sr_export.py" if model.key == "PISA_SR" else "moge3_export.py"
+        exporter, arguments = ISOLATED_EXPORTERS[model.key]
         with TemporaryDirectory(prefix=f".{model.folder}-", dir=MODELS_DIR) as directory:
             subprocess.run(
                 ["uv", "run", "--script", str(Path(__file__).with_name(exporter)),
-                 "--destination", directory],
+                 *arguments, "--destination", directory],
                 cwd=PROJECT_ROOT, check=True,
             )
             models = [item for item in MODEL_FILES if item.key == model.key]
             for item in models:
                 if not verify_file(Path(directory) / item.filename, item.size, item.sha256):
                     raise RuntimeError(f"{model.key} export differs from the published catalog")
-            for path in Path(directory).iterdir():
-                path.replace(model.destination.parent / path.name)
+            for item in models:
+                path = Path(directory) / item.filename
+                destination = MODELS_DIR / item.folder / item.filename
+                destination.parent.mkdir(parents=True, exist_ok=True)
+                path.replace(destination)
         return
     if not model.source_url:
         raise RuntimeError(f"No upstream source or builder for {model.key}")