Reapply "Integrated the GraphML Visualizer as an optional component of LightRAG"

This reverts commit b2bc7770fd.

setup.py

@@ -62,6 +62,16 @@ def read_api_requirements():
     return api_deps
 
 
+def read_extra_requirements():
+    api_deps = []
+    try:
+        with open("./lightrag/extra/VisualizationTool/requirements.txt") as f:
+            api_deps = [line.strip() for line in f if line.strip()]
+    except FileNotFoundError:
+        print("Warning: API requirements.txt not found.")
+    return api_deps
+
+
 metadata = retrieve_metadata()
 long_description = read_long_description()
 requirements = read_requirements()
@@ -97,10 +107,12 @@ setuptools.setup(
     },
     extras_require={
         "api": read_api_requirements(),  # API requirements as optional
+        "tools": read_extra_requirements(),  # API requirements as optional
     },
     entry_points={
         "console_scripts": [
             "lightrag-server=lightrag.api.lightrag_server:main [api]",
+            "lightrag-viewer=lightrag.tools.lightrag_visualizer:main [tools]",
         ],
     },
 )