Initial commit: Add AI agent framework documentation

- Add .gitignore with Python, IDE, and AI agent ignores
- Add core documentation files for the AI agent framework

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

HEARTBEAT.md

@@ -0,0 +1,5 @@
+# HEARTBEAT.md
+
+# Keep this file empty (or with only comments) to skip heartbeat API calls.
+
+# Add tasks below when you want the agent to check something periodically.