ci: validate PyAutoMemory on Python 3.12

Run the validation workflow on the ecosystem minimum Python and recognize the shared root AI policy in the repository layout.

Author: Jammy2211

.github/workflows/validate.yml

@@ -12,7 +12,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.11"
+          python-version: "3.12"
       - run: pip install pytest
       - run: make validate
       - run: make test

scripts/validate_structure.py

@@ -27,6 +27,7 @@
 ALLOWED_TOP_FILES = {
     ".gitignore",
     "AGENTS.md",
+    "AI_POLICY.md",
     "CLAUDE.md",
     "CONTRIBUTING.md",
     "LICENSE",