Install Node 22 from NodeSource in project base image

Bookworm's apt nodejs is 18.x; frontend toolchains after the 2026-07-15
dependency upgrades (vite 7) require Node >= 20, so any sled building a
frontend via build.rs failed. NodeSource nodejs bundles npm, so the
separate apt npm package is dropped.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019fHdm92yjvguPi2LiXfLB9

docker/Dockerfile.base

@@ -27,8 +27,13 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         procps \
         openssh-server \
         sudo \
-        nodejs \
-        npm \
+    && rm -rf /var/lib/apt/lists/*
+
+# Node.js 22.x from NodeSource — bookworm's apt nodejs is 18.x, which modern
+# frontend toolchains (vite ≥ 7) refuse to run under. Project builds that
+# shell out to npm (e.g. build.rs frontend steps) need ≥ 20.
+RUN curl -fsSL https://deb.nodesource.com/setup_22.x | bash - \
+    && apt-get install -y --no-install-recommends nodejs \
     && npm install -g @anthropic-ai/claude-code \
     && rm -rf /var/lib/apt/lists/*