Add AGENTS.md with dev environment setup instructions

[FluffyAIcode]

Adds AGENTS.md with Cursor Cloud specific instructions for future agents working in this repository.

What's included

• Project overview (pure Python research codebase, no external services)
• Instructions for running all standalone modules (perceptual_memory_benchmark.py, k3m_codec.py, constraint_edge_volume.py)
• Notes on modules requiring external data (LongMemEval dataset, MemPalace dialect)
• Key gotchas (no test suite, mempalace.dialect import-time crash without env var, use python3 not python)

Environment verification

All three core modules were tested successfully:

dev_env_test_output.log

_{To show artifacts inline, enable in settings.}