ci: pin Python version to 3.13.5 across all workflows

- Update all GitHub Actions workflows to use Python 3.13.5 specifically
- Replace flexible '3.13' with exact '3.13.5' version pinning
- Update pyproject.toml requires-python and classifiers to match
- Align CI/CD with local development environment (Python 3.13.5)
- Prevent Dependabot from testing with newer Python versions like 3.13.12

pyproject.toml

@@ -110,7 +110,7 @@ authors = [
 ]
 readme = "cli/README.md"
 license = "MIT"
-requires-python = ">=3.13"
+requires-python = ">=3.13.5"
 dependencies = [
     "click==8.3.1",
     "httpx==0.28.1",
@@ -135,7 +135,7 @@ classifiers = [
     "Development Status :: 4 - Beta",
     "Intended Audience :: Developers",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.13.5",
     "Operating System :: OS Independent",
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Topic :: System :: Distributed Computing",