feat: Add Bioxel asset catalog and layer management functionality

- Introduced a new asset catalog definition file for Blender to manage Bioxel assets.
- Implemented layer caching and snapshot functionality in `layer.py`, allowing for VDB file generation and low-resolution snapshots.
- Created node management functions in `node.py` for handling Bioxel nodes within Blender's Geometry Node Editor.
- Added an operator to extract mesh data from selected nodes in `structure.py`.
- Developed UI panels in `panels.py` for layer management, including import options and layer library display.

pack.py

@@ -0,0 +1,92 @@
+"""
+Create a zip archive of the src/bioxelnodes package with a top-level folder
+named `bioxelnodes/`. Excludes specified temporary/cache files and folders.
+Does not modify any files in the project.
+
+Usage:
+    python build_package.py <platform_name> [output_zip_path]
+
+Example:
+    python build_package.py windows-x64
+"""
+from pathlib import Path
+import sys
+import zipfile
+import fnmatch
+from datetime import datetime
+
+platforms = {
+    "windows-x64": "windows-x64",
+    "linux-x64": "linux-x64",
+    "macos-arm64": "macos-arm64",
+    "macos-x64": "macos-x64",
+}
+
+# patterns to exclude (filename matching)
+EXCLUDE_FILENAME_PATTERNS = [
+    "*.blend1",
+    "blendcache_*",
+    "*.cats.txt~",
+    "*.pyc",
+    "*.pyo",
+    "*$py.class",
+]
+
+# directory names to exclude entirely
+EXCLUDE_DIR_NAMES = {
+    "__pycache__",
+}
+
+def should_exclude(path: Path) -> bool:
+    name = path.name
+    # exclude directories by name anywhere in the path
+    if any(part in EXCLUDE_DIR_NAMES for part in path.parts):
+        return True
+    # only apply filename patterns to files
+    if path.is_file():
+        for pat in EXCLUDE_FILENAME_PATTERNS:
+            if fnmatch.fnmatch(name, pat):
+                return True
+    return False
+
+def build_package(platform_name: str, out_zip: Path):
+    src_root = Path("src") / "bioxelnodes"
+    if not src_root.exists():
+        raise SystemExit(f"Source folder not found: {src_root.resolve()}")
+
+    out_zip.parent.mkdir(parents=True, exist_ok=True)
+    total = 0
+    with zipfile.ZipFile(out_zip, "w", compression=zipfile.ZIP_DEFLATED) as zf:
+        for p in src_root.rglob("*"):
+            if p.is_dir():
+                continue
+            if should_exclude(p):
+                continue
+            # arcname should place files under top-level 'bioxelnodes/...'
+            rel = p.relative_to(src_root)
+            arcname = Path("bioxelnodes") / rel
+            zf.write(p, arcname.as_posix())
+            total += 1
+    print(f"Packaged {total} files into {out_zip}")
+
+def main():
+    if len(sys.argv) < 2:
+        print("Usage: python build_package.py <platform_name> [output_zip_path]")
+        print("Available platforms:", ", ".join(platforms.keys()))
+        sys.exit(1)
+
+    platform_key = sys.argv[1]
+    if platform_key not in platforms:
+        print("Unknown platform:", platform_key)
+        print("Available platforms:", ", ".join(platforms.keys()))
+        sys.exit(1)
+
+    tag = platforms[platform_key]
+    timestamp = datetime.now().strftime("%Y%m%dT%H%M%S")
+    default_name = f"bioxelnodes-{tag}-{timestamp}.zip"
+    out_path = Path(sys.argv[2]) if len(sys.argv) >= 3 else Path(default_name)
+
+    build_package(platform_key, out_path)
+
+if __name__ == "__main__":
+    main()