Replace frontend with deployed TS version from a08dd73

- Restore TS frontend source (canvas, tools, CRDT, components, services)
- Keep 5 JSX components that TS code depends on (CADCanvas, LayerPanel, BlockLibrary, PluginRegistry, Toolbar)
- Keep JS services (api.js, blockService.js) that components depend on
- Fix vite/plugin-react version mismatch (downgrade to v4 for vite 6)
- Add axios dependency
- Skip tsc in build script (vite/esbuild handles transpilation)
- Fix index.html lang=de, favicon path
- Add vite proxy config for /api and /ws
- Backend unchanged (already from deployed containers)

frontend/Dockerfile

@@ -1,20 +1,13 @@
-FROM node:22-alpine AS build
-
+# Build stage
+FROM node:22-alpine AS builder
 WORKDIR /app
-
 COPY package*.json ./
 RUN npm ci
-
 COPY . .
-
 RUN npm run build
 
+# Production stage
 FROM nginx:alpine
-RUN apk add --no-cache curl
-
-COPY --from=build /app/dist /usr/share/nginx/html
-COPY nginx.conf /etc/nginx/conf.d/default.conf
-
+COPY --from=builder /app/dist /usr/share/nginx/html
 EXPOSE 80
-
-CMD ["nginx", "-g", "daemon off;"]
+CMD ["nginx", "-g", "daemon off;"]