refactor: migrate Information package and add repo path helpers

Move GHSA/NVD fetchers under pure_auto_codeql.information with
top-level re-export shims. Introduce get_repo_root/prompts_dir and
fix codeql_gen_agents prompt path resolution after nested package layout.

Author: bx33661

Information/__init__.py

@@ -1 +1,9 @@
-"""Helper modules for vulnerability intelligence fetchers."""
+"""Legacy GHSA/NVD intelligence package.
+
+Implementation lives under ``pure_auto_codeql.information``. This top-level
+package re-exports the same modules for compatibility.
+"""
+
+from pure_auto_codeql.information import ghsa_fetch, nvd_info_fetch
+
+__all__ = ["ghsa_fetch", "nvd_info_fetch"]