fix: Use absolute paths in nano-graphrag setup.py

- Fix requirements.txt path resolution using os.path.join
- Fix readme.md and __init__.py path resolution
- Should resolve "No such file or directory" errors during installation

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

nano-graphrag/setup.py

@@ -1,13 +1,17 @@
 import setuptools
 from setuptools import find_packages
 
-with open("readme.md", "r") as fh:
+import os
+
+readme_path = os.path.join(os.path.dirname(__file__), "readme.md")
+with open(readme_path, "r") as fh:
     long_description = fh.read()
 
 
 vars2find = ["__author__", "__version__", "__url__"]
 vars2readme = {}
-with open("./nano_graphrag/__init__.py") as f:
+init_path = os.path.join(os.path.dirname(__file__), "nano_graphrag", "__init__.py")
+with open(init_path) as f:
     for line in f.readlines():
         for v in vars2find:
             if line.startswith(v):
@@ -15,7 +19,9 @@ with open("./nano_graphrag/__init__.py") as f:
                 vars2readme[v] = line.split("=")[1]
 
 deps = []
-with open("./requirements.txt") as f:
+# Use absolute path to requirements.txt
+requirements_path = os.path.join(os.path.dirname(__file__), "requirements.txt")
+with open(requirements_path) as f:
     for line in f.readlines():
         if not line.strip():
             continue