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-init.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+set -e
+
+CODER="go run ./cmd/coder"
+PASSWORD="${CODER_DEV_ADMIN_PASSWORD:-SomeSecurePassword!}"
+TOKEN_FILE="/bootstrap/token"
+TOKEN_NAME="bootstrap"
+
+echo "=== Coder Dev Environment Init ==="
+
+if curl -s -o /dev/null -w "%{http_code}" http://coderd:3000/api/v2/users/first | grep -q "200"; then
+	echo "First user already exists, skipping setup"
+	exit 0
+fi
+
+# Step 1: Create first user (idempotent - creates OR logs in)
+echo "Creating/logging in first user..."
+$CODER login http://coderd:3000 \
+	--first-user-username=admin \
+	--first-user-email=admin@coder.com \
+	--first-user-password="$PASSWORD" \
+	--first-user-full-name="Admin User" \
+	--first-user-trial=false
+
+# Step 2: Create or retrieve bootstrap token
+if [ -f "$TOKEN_FILE" ] && [ -s "$TOKEN_FILE" ]; then
+	echo "Bootstrap token already exists."
+else
+	echo "Creating bootstrap token..."
+	# Delete existing token if it exists (in case file was lost but token exists)
+	$CODER tokens delete "$TOKEN_NAME" 2>/dev/null || true
+	# Create new token with no expiry
+	TOKEN=$($CODER tokens create --name "$TOKEN_NAME" --lifetime 0)
+	echo "$TOKEN" >"$TOKEN_FILE"
+	echo "Bootstrap token created and saved."
+fi
+
+echo "=== Init complete ==="