feat(admin): integrate Next.js admin panel (admin-next/) from feat/nextjs-admin

- Add admin-next/: full Next.js + Prisma + shadcn admin panel (45 API routes, 76 components)
- docker-compose: tg_shop_admin service (port 3000, shared db/shop.db, prisma), bot talks to it via ADMIN_CHAT_URL=http://tg_shop_admin:3000/api/chat
- tor-proxy now proxies onion admin to tg_shop_admin:3000 (new panel)
- chatbotService: ADMIN_CHAT_URL default = http://tg_shop_admin:3000/api/chat (removed localhost:3100 anachronism)
- .env admin secrets gitignored (admin-next/.env)

admin-next/Dockerfile

@@ -0,0 +1,59 @@
+# --- Stage 1: Build ---
+FROM node:22-slim AS builder
+
+WORKDIR /app
+
+# Install bun for faster installs
+RUN npm install -g bun
+
+# Install dependencies
+COPY package.json bun.lock ./
+RUN bun install --frozen-lockfile
+
+# Copy source
+COPY prisma ./prisma/
+COPY tsconfig.json next.config.ts postcss.config.mjs tailwind.config.ts components.json ./
+COPY public ./public/
+COPY src ./src/
+
+# Generate Prisma client
+RUN npx prisma generate
+
+# Build Next.js (output: standalone)
+RUN npx next build
+
+# Copy static assets into standalone
+RUN cp -r .next/static .next/standalone/.next/ && \
+    cp -r public .next/standalone/
+
+# --- Stage 2: Production ---
+FROM node:22-slim AS runner
+
+WORKDIR /app
+
+ENV NODE_ENV=production
+ENV PORT=3000
+ENV HOSTNAME="0.0.0.0"
+
+# Create non-root user
+RUN addgroup --system --gid 1001 nodejs && \
+    adduser --system --uid 1001 nextjs
+
+# Copy standalone output
+COPY --from=builder /app/.next/standalone ./
+
+# Copy static files
+COPY --from=builder /app/.next/standalone/.next ./.next
+
+# Copy Prisma schema for potential migrations
+COPY --from=builder /app/prisma ./prisma/
+
+# Create db directory
+RUN mkdir -p /app/db && chown nextjs:nodejs /app/db
+
+# Switch to non-root
+USER nextjs
+
+EXPOSE 3000
+
+CMD ["node", "server.js"]