feat: initial scaffold - backend, frontend, Prisma schema, Docker

- Prisma schema: User, Session, RepoConfig, Preview, Job, WebhookToken, NoConfigComment, AdminSettings
- Backend: auth (login/logout/me/first-user setup), webhook handler with HMAC verification, EC2 service, SSH service, deploy pipeline, job queue worker, cron workers
- Frontend: Login with first-user detection, Dashboard, PreviewDetail with live log streaming, Settings, Repos config, Admin panel, SetupWizard, Privacy page
- Docker Compose and Dockerfile for self-hosted deployment
- Uses bcryptjs for Node 24 compatibility

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

Dockerfile

@@ -0,0 +1,30 @@
+FROM node:24-alpine AS frontend-builder
+WORKDIR /app/frontend
+COPY frontend/package.json frontend/pnpm-lock.yaml* ./
+RUN npm install -g pnpm && pnpm install --frozen-lockfile
+COPY frontend/ ./
+RUN pnpm build
+
+FROM node:24-alpine AS backend-builder
+WORKDIR /app/backend
+COPY backend/package.json backend/pnpm-lock.yaml* ./
+RUN npm install -g pnpm && pnpm install --frozen-lockfile
+COPY backend/ ./
+COPY prisma/ ../prisma/
+RUN pnpm run generate && pnpm run build
+
+FROM node:24-alpine AS runner
+WORKDIR /app
+RUN apk add --no-cache openssl
+
+COPY --from=backend-builder /app/backend/dist ./backend/dist
+COPY --from=backend-builder /app/backend/node_modules ./backend/node_modules
+COPY --from=backend-builder /app/backend/package.json ./backend/package.json
+COPY --from=frontend-builder /app/frontend/dist ./frontend/dist
+COPY prisma/ ./prisma/
+
+WORKDIR /app/backend
+
+EXPOSE 5000
+
+CMD sh -c "npx prisma migrate deploy --schema=../prisma/schema.prisma && node dist/index.js"