Fix gh config directory ownership in devcontainer

Create /home/node/.config/gh in Dockerfile and set node ownership
so the directory is writable when mounted as a named volume.

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

Author: shugo

.devcontainer/Dockerfile

@@ -62,8 +62,8 @@ RUN SNIPPET="export PROMPT_COMMAND='history -a' && export HISTFILE=/commandhisto
 ENV DEVCONTAINER=true
 
 # Create workspace and config directories and set permissions
-RUN mkdir -p /workspace /home/node/.claude && \
-  chown -R node:node /workspace /home/node/.claude
+RUN mkdir -p /workspace /home/node/.claude /home/node/.config/gh && \
+  chown -R node:node /workspace /home/node/.claude /home/node/.config/gh
 
 WORKDIR /workspace