Fix API URL config: use Next.js rewrite proxy instead of NEXT_PUBLIC_*

NEXT_PUBLIC_* is baked at build time so runtime docker-compose environment
vars have no effect. Instead:
- next.config.ts rewrites /api/* -> API_BASE_URL/api/* at the server level
- api.ts uses relative paths (no env var in client bundle at all)
- docker-compose passes API_BASE_URL=http://cvfs-backend:8080 at runtime
- Dockerfile no longer needs any build args

Requests: browser -> Next.js server (/api/*) -> cvfs-backend:8080 (/api/*)

https://claude.ai/code/session_01Xmxm2QLgFBgRJyYD6VukR6

apps/webapp/next.config.ts

@@ -3,6 +3,10 @@ import path from "node:path";
 
 const nextConfig: NextConfig = {
   outputFileTracingRoot: path.join(process.cwd(), "../.."),
+  async rewrites() {
+    const backend = process.env.API_BASE_URL ?? "http://localhost:9812";
+    return [{ source: "/api/:path*", destination: `${backend}/api/:path*` }];
+  },
 };
 
 export default nextConfig;

apps/webapp/src/libs/api.ts

@@ -1,4 +1,6 @@
-const API = process.env.NEXT_PUBLIC_API_BASE_URL ?? "http://localhost:9812";
+// Empty base: all API calls go to /api/* which Next.js rewrites to the backend.
+// The actual backend URL is set via API_BASE_URL env var in next.config.ts (server-side, runtime).
+const API = "";
 
 export type StructuredBlock = {
     path: string;
@@ -130,4 +132,3 @@ export async function publishVersion(
     });
 }
 
-export { API as API_BASE_URL };

docker-compose.yml

@@ -11,8 +11,8 @@ services:
     build:
       context: ./
       dockerfile: ./docker/webapp.Dockerfile
-      args:
+    environment:
-        - NEXT_PUBLIC_API_BASE_URL=https://api.cv.alves.world
+      - API_BASE_URL=http://cvfs-backend:8080
     networks:
       - dokploy-network
       - cvfs-network

docker/webapp.Dockerfile

@@ -8,8 +8,6 @@ COPY apps/webapp/package.json apps/webapp/bun.lock ./
 RUN bun install --frozen-lockfile
 
 FROM deps AS builder
-ARG NEXT_PUBLIC_API_BASE_URL=http://localhost:9812
-ENV NEXT_PUBLIC_API_BASE_URL=$NEXT_PUBLIC_API_BASE_URL
 COPY apps/webapp ./
 RUN bun run build