feat(agent): add provider templates

Assisted-by: Codex

Dockerfile.codex

@@ -0,0 +1,20 @@
+# claude-bottle Codex provider image.
+#
+# Mirrors the default Claude image shape: Node LTS, git/network tooling,
+# non-root node user, and the provider CLI installed globally.
+
+FROM node:22-slim
+
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends git ca-certificates openssh-client socat curl dnsutils \
+  && rm -rf /var/lib/apt/lists/*
+
+RUN npm install -g --no-fund --no-audit @openai/codex@0.134.0 \
+  && npm cache clean --force
+
+USER node
+WORKDIR /home/node
+
+RUN mkdir -p /home/node/.codex
+
+CMD ["codex"]