fix(docker): publish spawn-pi image so --beta sandbox works for pi

.github/workflows/docker.yml

@@ -20,7 +20,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        agent: [claude, codex, cursor, openclaw, opencode, kilocode, hermes, junie]
+        agent: [claude, codex, cursor, openclaw, opencode, kilocode, hermes, junie, pi]
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4
 

sh/docker/pi.Dockerfile

@@ -0,0 +1,17 @@
+FROM ubuntu:24.04
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Base packages
+RUN apt-get update -y && \
+    apt-get install -y --no-install-recommends \
+      curl git ca-certificates build-essential unzip zsh && \
+    rm -rf /var/lib/apt/lists/*
+
+# Node.js 22 via n
+RUN curl --proto '=https' -fsSL https://raw.githubusercontent.com/tj/n/master/bin/n | bash -s install 22
+
+# Pi (pi-coding-agent)
+RUN npm install -g @mariozechner/pi-coding-agent
+
+CMD ["/bin/sleep", "inf"]