Remove nginx/webapp container; single Go server serves SPA + API

- Add root Dockerfile: node build → copy dist into Go embed path → distroless binary
- Update docker-compose: one service (api on :9050), DB renamed ralph→pamietnik
- Remove references to RALPH/reisejournal across all docs and configs

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

docker-compose.yml

@@ -2,34 +2,30 @@ services:
   postgres:
     image: postgres:16-alpine
     environment:
-      POSTGRES_USER: ralph
-      POSTGRES_PASSWORD: ralph
-      POSTGRES_DB: ralph
+      POSTGRES_USER: pamietnik
+      POSTGRES_PASSWORD: pamietnik
+      POSTGRES_DB: pamietnik
     volumes:
       - pgdata:/var/lib/postgresql/data
     healthcheck:
-      test: ["CMD-SHELL", "pg_isready -U ralph"]
+      test: ["CMD-SHELL", "pg_isready -U pamietnik"]
       interval: 5s
       timeout: 5s
       retries: 5
 
   api:
-    build: ./backend
+    build:
+      context: .
+      dockerfile: Dockerfile
+    ports:
+      - "9050:8080"
     environment:
-      DATABASE_URL: postgres://ralph:ralph@postgres:5432/ralph?sslmode=disable
+      DATABASE_URL: postgres://pamietnik:pamietnik@postgres:5432/pamietnik?sslmode=disable
       LISTEN_ADDR: :8080
     depends_on:
       postgres:
         condition: service_healthy
     restart: unless-stopped
 
-  webapp:
-    build: ./webapp
-    ports:
-      - "9050:80"
-    depends_on:
-      - api
-    restart: unless-stopped
-
 volumes:
   pgdata: