refactor(workspace): restore yaml exports and align docker builds

- return scenario export payloads as yaml to match existing workflows

- harden step reordering flow for drag-and-drop and one-based ui labels

- switch server container to workspace-lockfile installs and root ignore rules

server/Dockerfile

@@ -4,11 +4,13 @@ FROM node:22-slim AS builder
 WORKDIR /app
 
 COPY package*.json ./
-RUN npm ci
+COPY server/package.json ./server/
+RUN npm ci -w server
 
-COPY nest-cli.json tsconfig*.json ./
-COPY src ./src
-RUN npm run build
+COPY server/nest-cli.json ./server/
+COPY server/tsconfig*.json ./server/
+COPY server/src ./server/src
+RUN npm run -w server build
 
 # ── Runtime stage ─────────────────────────────────────────────────────────────
 FROM node:22-slim AS runtime
@@ -27,9 +29,10 @@ ENV PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH=/usr/bin/chromium
 WORKDIR /app
 
 COPY package*.json ./
-RUN npm ci --omit=dev
+COPY server/package.json ./server/
+RUN npm ci --omit=dev -w server
 
-COPY --from=builder /app/dist ./dist
+COPY --from=builder /app/server/dist ./dist
 
 # Runtime directories (keys and SQLite DB mounted via volumes)
 RUN mkdir -p data keys