Drop Python 3.9 support, require Python 3.10+

Python 3.9 reached end-of-life and the codebase uses PEP 604 union
type syntax (str | None) which requires Python 3.10+.

Changes:
- Remove Python 3.9 from CI build matrix
- Update requires-python to >=3.10 in all pyproject.toml files
- Update classifiers to reflect supported Python versions (3.10-3.13)

.github/workflows/build-reusable.yml

@@ -35,8 +35,8 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: ubuntu-22.04
-            python: '3.9'
+          # Note: Python 3.9 dropped - uses PEP 604 union syntax (str | None)
+          # which requires Python 3.10+
           - os: ubuntu-22.04
             python: '3.10'
           - os: ubuntu-22.04
@@ -46,8 +46,6 @@ jobs:
           - os: ubuntu-22.04
             python: '3.13'
           # ARM64 Linux builds
-          - os: ubuntu-24.04-arm
-            python: '3.9'
           - os: ubuntu-24.04-arm
             python: '3.10'
           - os: ubuntu-24.04-arm
@@ -56,8 +54,6 @@ jobs:
             python: '3.12'
           - os: ubuntu-24.04-arm
             python: '3.13'
-          - os: macos-14
-            python: '3.9'
           - os: macos-14
             python: '3.10'
           - os: macos-14
@@ -66,8 +62,6 @@ jobs:
             python: '3.12'
           - os: macos-14
             python: '3.13'
-          - os: macos-15
-            python: '3.9'
           - os: macos-15
             python: '3.10'
           - os: macos-15
@@ -76,8 +70,6 @@ jobs:
             python: '3.12'
           - os: macos-15
             python: '3.13'
-          - os: macos-13
-            python: '3.9'
           - os: macos-13
             python: '3.10'
           - os: macos-13

packages/leann-core/pyproject.toml

@@ -7,7 +7,7 @@ name = "leann-core"
 version = "0.3.5"
 description = "Core API and plugin system for LEANN"
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 license = { text = "MIT" }
 
 # All required dependencies included

packages/leann/pyproject.toml

@@ -7,7 +7,7 @@ name = "leann"
 version = "0.3.5"
 description = "LEANN - The smallest vector index in the world. RAG Everything with LEANN!"
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 license = { text = "MIT" }
 authors = [
     { name = "LEANN Team" }
@@ -18,10 +18,10 @@ classifiers = [
     "Intended Audience :: Developers",
     "License :: OSI Approved :: MIT License",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
 ]
 
 # Default installation: core + hnsw + diskann

pyproject.toml

@@ -5,7 +5,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "leann-workspace"
 version = "0.1.0"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 
 dependencies = [
     "leann-core",