Add SnapForm panels, preferences, properties, and runtime management

- Implemented RuntimeModelsPanel and DebugPanel for UI integration in Blender.
- Created SnapFormPreferences to manage user settings for storage and runtime configuration.
- Defined SnapFormSettings to hold various properties related to input, model selection, and export options.
- Developed runtime management functions for installation, model downloading, and reconstruction commands.
- Added status bar functionality to display job progress and status in the Blender UI.
- Implemented worker script for handling model downloads and depth reconstruction tasks.
- Introduced unit tests for download progress reporting and image depth extraction functionalities.

src/snapform/models.py

@@ -0,0 +1,81 @@
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class ModelSpec:
+    key: str
+    label: str
+    repository: str
+    license_name: str
+    description: str
+    supports_gs: bool
+
+
+MODELS = {
+    "SMALL": ModelSpec(
+        key="SMALL",
+        label="DA3 Small",
+        repository="depth-anything/DA3-SMALL",
+        license_name="Apache 2.0",
+        description="Fastest any-view model with Apache 2.0 weights",
+        supports_gs=False,
+    ),
+    "BASE": ModelSpec(
+        key="BASE",
+        label="DA3 Base",
+        repository="depth-anything/DA3-BASE",
+        license_name="Apache 2.0",
+        description="Balanced any-view model with Apache 2.0 weights",
+        supports_gs=False,
+    ),
+    "LARGE_1_1": ModelSpec(
+        key="LARGE_1_1",
+        label="DA3 Large 1.1",
+        repository="depth-anything/DA3-LARGE-1.1",
+        license_name="CC BY-NC 4.0",
+        description="Higher quality non-commercial model with larger VRAM use",
+        supports_gs=False,
+    ),
+    "GIANT_1_1": ModelSpec(
+        key="GIANT_1_1",
+        label="DA3 Giant 1.1",
+        repository="depth-anything/DA3-GIANT-1.1",
+        license_name="CC BY-NC 4.0",
+        description="Non-commercial Giant model with Gaussian head",
+        supports_gs=True,
+    ),
+    "NESTED_GIANT_LARGE_1_1": ModelSpec(
+        key="NESTED_GIANT_LARGE_1_1",
+        label="DA3 Nested Giant Large 1.1",
+        repository="depth-anything/DA3NESTED-GIANT-LARGE-1.1",
+        license_name="CC BY-NC 4.0",
+        description="Non-commercial nested model with metric depth and Gaussian head",
+        supports_gs=True,
+    ),
+}
+
+
+def enum_items(supports_gs=None):
+    return [
+        (
+            model.key,
+            model.label,
+            f"{model.description}; license: {model.license_name}",
+        )
+        for model in MODELS.values()
+        if supports_gs is None or model.supports_gs == supports_gs
+    ]
+
+
+def selected_model_key(settings, export_format=None):
+    selected_format = export_format or settings.export_format
+    if selected_format == "gs_ply":
+        return settings.gs_model
+    return settings.model
+
+
+def get_model(model_key):
+    try:
+        return MODELS[model_key]
+    except KeyError as error:
+        raise ValueError(f"Unknown DA3 model: {model_key}") from error