chore: initial commit of foundryvtt-admin

Spun out of the hbm-books working folder into its own repo. A small
backend+frontend+COBOL admin tool for managing Foundry VTT worlds
(socket inspection, join/shutdown debugging).

cobol/Dockerfile

@@ -0,0 +1,4 @@
+FROM alpine:latest
+RUN apk add --no-cache gnucobol build-base curl
+WORKDIR /app
+CMD ["sh", "-c", "echo 'COBOL Container Ready. Shared files are in /app/shared.' && sh"]