scripts: run_demo.sh launcher (no python on PATH needed), friendly port-in-use check in run_bridge.sh; README updated

scripts/run_bridge.sh

@@ -1,7 +1,25 @@
 #!/usr/bin/env bash
 # Start the AICC capsule testbed bridge over WebSocket (headless).
 # Usage: scripts/run_bridge.sh [port]   (default 8765)
+# Note: the bridge keeps running until interrupted (Ctrl-C).
 set -euo pipefail
 cd "$(dirname "$0")/.."
 PORT="${1:-8765}"
+
+if python3 - "$PORT" <<'EOF'
+import socket, sys
+port = int(sys.argv[1])
+s = socket.socket()
+if s.connect_ex(("127.0.0.1", port)) == 0:
+    print(f"port {port} is already in use")
+    sys.exit(1)
+EOF
+then
+    :
+else
+    echo "error: a bridge may already be running on port $PORT." >&2
+    echo "stop it first, e.g.:  fuser -k ${PORT}/tcp   (or kill the run_bridge.sh process)" >&2
+    exit 1
+fi
+
 exec testbed/.venv/bin/python -m testbed.bridge --host 127.0.0.1 --port "$PORT"

scripts/run_demo.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+# Run the AICC capsule demo (agent drives the capsule to the beacon).
+# Usage: scripts/run_demo.sh [demo args...]
+#   e.g. scripts/run_demo.sh --agent auto
+#        scripts/run_demo.sh --agent scripted
+#        scripts/run_demo.sh --agent llm --model gemma4:e2b
+set -euo pipefail
+cd "$(dirname "$0")/.."
+exec testbed/.venv/bin/python -m testbed.demo "$@"

scripts/setup.sh

@@ -14,5 +14,5 @@ pip install pillow websockets openai pytest pytest-asyncio
 
 echo "Setup done. Activate with: source testbed/.venv/bin/activate"
 echo "Run the bridge:  scripts/run_bridge.sh"
-echo "Run the demo:    testbed/.venv/bin/python -m testbed.demo --agent auto"
+echo "Run the demo:    scripts/run_demo.sh --agent auto"
 echo "Conformance:     testbed/.venv/bin/python -m testbed.conformance ~/Desktop/aicc-spec/conformance/scenarios"