fix: diskann build and prevent termination from hanging

- Fix OpenMP library linking in DiskANN CMake configuration
- Add timeout protection for HuggingFace model loading to prevent hangs
- Improve embedding server process termination with better timeouts
- Make DiskANN backend default enabled alongside HNSW
- Update documentation to reflect both backends included by default

packages/leann/pyproject.toml

@@ -24,16 +24,15 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
 ]
 
-# Default installation: core + hnsw
+# Default installation: core + hnsw + diskann
 dependencies = [
     "leann-core>=0.1.0",
     "leann-backend-hnsw>=0.1.0",
+    "leann-backend-diskann>=0.1.0",
 ]
 
 [project.optional-dependencies]
-diskann = [
-    "leann-backend-diskann>=0.1.0",
-]
+# All backends now included by default
 
 [project.urls]
 Repository = "https://github.com/yichuan-w/LEANN"