Consolidate tools into a secure Docker architecture with landing page

- Implement a central reverse proxy (Nginx) with Basic Auth on port 8090.
- Create a unified landing page (dashboard) to access B2B Assistant and Market Intelligence.
- Update frontends with relative API paths and base paths for subdirectory routing (/b2b/, /market/).
- Optimize Docker builds with .dockerignore and a Python-based image for market-backend.
- Enable code sideloading for Python logic via Docker volumes.
- Fix TypeScript errors in general-market-intelligence regarding ImportMeta.

nginx-proxy.conf

@@ -0,0 +1,44 @@
+events {
+    worker_connections 1024;
+}
+
+http {
+    include       mime.types;
+    default_type  application/octet-stream;
+    
+    access_log /dev/stdout;
+    error_log /dev/stderr;
+
+    # Resolver ist wichtig für Docker
+    resolver 127.0.0.11 valid=30s ipv6=off;
+
+    server {
+        listen 80;
+
+        # Basic Auth wieder aktiviert
+        auth_basic "Restricted Access - Local AI Suite";
+        auth_basic_user_file /etc/nginx/.htpasswd;
+
+        location / {
+            proxy_pass http://dashboard:80;
+            proxy_set_header Host $host;
+            proxy_set_header X-Real-IP $remote_addr;
+        }
+
+        location /b2b/ {
+            # Der Trailing Slash am Ende ist wichtig!
+            proxy_pass http://b2b-app:3002/;
+            proxy_set_header Host $host;
+            proxy_set_header Upgrade $http_upgrade;
+            proxy_set_header Connection "upgrade";
+        }
+
+        location /market/ {
+            # Der Trailing Slash am Ende ist wichtig!
+            proxy_pass http://market-frontend:80/;
+            proxy_set_header Host $host;
+            proxy_set_header Upgrade $http_upgrade;
+            proxy_set_header Connection "upgrade";
+        }
+    }
+}