fix: mkdir /data dirs at runtime for S3-mounted volumes

The Dockerfile pre-creates /data/opencode and /data/workspaces but
in production /data is replaced by an S3-backed mount at container
start, so those directories vanish. Restore mkdir -p in the
entrypoint so they exist before opencode tries to open its database.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: gluonfield

entrypoint.sh

@@ -4,6 +4,7 @@ set -e
 : "${OPENROUTER_BASE_URL:?OPENROUTER_BASE_URL is required}"
 : "${OPENROUTER_API_KEY:?OPENROUTER_API_KEY is required}"
 
+mkdir -p /data/opencode /data/workspaces
 export OPENCODE_DB=/data/opencode/opencode.db
 
 cat > /home/sandbox/.config/opencode/opencode.json <<EOF