draggable topology + attack visualizer + tools in containers

- topology nodes draggable (pointer events, SVG transform), layout hint shown
- attack visualizer: /api/attacks logs attacker->target events; red pulsing
  dashed arcs on recent attacks (60s hot), ⚔ counts ok/fail
- submit_flag now takes attacker_idx vs target_idx (A/D semantics); UI has
  target dropdown (enemy teams), leaderboard records target
- containers get vim+curl+wget+netcat+git+pip3 (Dockerfiles blogpost/cdn/
  phew/sheesh/warmup); warmup base ubuntu:20.04 EOL -> 24.04
- team portal: target dropdown refreshed after login (was empty pre-auth)

services/sheesh/Dockerfile

@@ -12,6 +12,11 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     libssl-dev \
     python3-dev \
     socat \
+    vim \
+    curl \
+    wget \
+    netcat-openbsd \
+    git \
     bash \
     && rm -rf /var/lib/apt/lists/*