fix: correct node path in supervisor, remove debian default sshd jail

- supervisor.conf: node is at /usr/local/bin/node in node:18-slim, not /usr/bin/node
- Dockerfile: remove /etc/fail2ban/jail.d/defaults-debian.conf at build time
  to prevent fail2ban crashing on missing sshd log file

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

Dockerfile

@@ -23,7 +23,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
       iptables \
       ipset \
       curl \
-    && rm -rf /var/lib/apt/lists/*
+    && rm -rf /var/lib/apt/lists/* \
+    # Remove debian default jail (enables sshd which has no log file in container)
+    && rm -f /etc/fail2ban/jail.d/defaults-debian.conf
 
 # ── Dashboard dependencies ────────────────────────────────────────────────────
 WORKDIR /app

supervisor.conf

@@ -39,7 +39,7 @@ priority=10
 
 # ── dashboard ─────────────────────────────────────────────────────────────────
 [program:dashboard]
-command=/usr/bin/node /app/server.js
+command=/usr/local/bin/node /app/server.js
 directory=/app
 autostart=true
 autorestart=true