docs: fix UI port from 8000 to 3001 in all docs

Frontend (React/nginx) is served on port 3001, not 8000.
Port 8000 is the backend FastAPI — API endpoint and /docs
references at 8000 are kept as-is since they are correct.

Fixed in: README.md, README.ru.md, WIKI.md (quick-start URL
and standalone deployment port description).

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

README.md

@@ -74,7 +74,7 @@ cp backend/.env.example backend/.env
 docker compose up -d
 
 # 4. Open
-# http://localhost:8000
+# http://localhost:3001
 # Default login: admin / admin123
 ```
 

README.ru.md

@@ -70,7 +70,7 @@ cp backend/.env.example backend/.env
 docker compose up -d
 
 # 4. Открываем
-# http://localhost:8000
+# http://localhost:3001
 # Вход по умолчанию: admin / admin123
 ```
 

WIKI.md

@@ -60,7 +60,7 @@ cp backend/.env.example backend/.env
 docker compose up -d
 
 # Open in browser
-open http://localhost:8000
+open http://localhost:3001
 ```
 
 **Default credentials:**
@@ -80,8 +80,8 @@ open http://localhost:8000
 ```bash
 docker compose up -d
 ```
-- Port: 8000
-- Without NGINX
+- UI port: 3001 (frontend), API port: 8000 (backend)
+- Without NGINX reverse proxy
 - Suitable for local development
 
 #### 2. With NGINX (HTTP)