chore: context pack for aicc-capsule reference testbed

- AGENTS.md: build instructions for AI coding agents
- docs/: AICC core spec copy, JSON schema, testbed design notes
- scripts/: setup.sh, BUILDLOG.md
- README.md: overview and reading order

scripts/setup.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# Setup script for aicc-capsule: create venv, install deps.
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+python3 -m venv testbed/.venv
+source testbed/.venv/bin/activate
+pip install --upgrade pip
+# aicc-py SDK from sibling checkout
+pip install -e "$HOME/Desktop/aicc-py"
+# Engine and demo deps go here (e.g. ursina, panda3d, pillow, websockets)
+# pip install ...
+
+echo "Setup done. Activate with: source testbed/.venv/bin/activate"