add SHELL env var to proxy for Claude Code Bash tool

Alpine doesn't set SHELL by default — Claude Code's Bash tool
refuses to run without it.

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

docker-compose.yml

@@ -21,6 +21,7 @@ services:
       - ./aria-data/ssh:/root/.ssh:ro               # SSH Keys fuer VM-Zugriff (aria-wohnung)
     environment:
       - HOST=0.0.0.0
+      - SHELL=/bin/sh                               # Claude Code Bash-Tool braucht SHELL-Variable
       - CLAUDE_CODE_BUBBLEWRAP=1                    # Erlaubt --dangerously-skip-permissions als root
     restart: unless-stopped
     networks: