chore: add compose alternative to develop.sh (#22157)

Adds a `compose.dev.yml` intended as a pure-Docker alternative to
`develop.sh`.

---------

Co-authored-by: Steven Masley <stevenmasley@gmail.com>

scripts/docker-dev/setup-template.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+set -e
+
+CODER="go run ./cmd/coder"
+TOKEN_FILE="/bootstrap/token"
+
+# Accept optional org argument. If not provided, use the user's default org.
+ORG_NAME="${1:-}"
+
+echo "=== Setting up docker template ==="
+
+# Load bootstrap token
+CODER_SESSION_TOKEN=$(cat "$TOKEN_FILE")
+if [ -z "${CODER_SESSION_TOKEN}" ]; then
+	echo "Bootstrap token not found in ${TOKEN_FILE}"
+	exit 1
+fi
+export CODER_SESSION_TOKEN
+
+# If no org provided, get user's default org.
+if [ -z "$ORG_NAME" ]; then
+	ORG_NAME=$($CODER organizations show me -o json | jq -r '.[] | select(.is_default) | .name')
+fi
+
+echo "Target organization: $ORG_NAME"
+
+# Check if template already exists in this org.
+if $CODER templates versions list docker --org "$ORG_NAME" >/dev/null 2>&1; then
+	echo "Docker template already exists in '$ORG_NAME'."
+	exit 0
+fi
+
+# Create and push docker template.
+echo "Creating docker template in '$ORG_NAME'..."
+TEMPLATE_DIR="$(mktemp -d)"
+$CODER templates init --id docker "$TEMPLATE_DIR"
+(cd "$TEMPLATE_DIR" && terraform init)
+
+ARCH="$(go env GOARCH)"
+printf 'docker_arch: "%s"\ndocker_host: "%s"\n' \
+	"$ARCH" "${DOCKER_HOST:-unix:///var/run/docker.sock}" \
+	>"$TEMPLATE_DIR/params.yaml"
+
+$CODER templates push docker \
+	--directory "$TEMPLATE_DIR" \
+	--variables-file "$TEMPLATE_DIR/params.yaml" \
+	--yes --org "$ORG_NAME"
+
+rm -rf "$TEMPLATE_DIR"
+echo "=== Docker template setup complete ==="