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.

Dockerfile.proxy

@@ -0,0 +1,9 @@
+FROM nginx:alpine
+
+# Install apache2-utils to generate .htpasswd natively
+RUN apk add --no-cache apache2-utils
+
+# Create the user 'admin' with password 'gemini' using bcrypt (most secure & compatible)
+RUN htpasswd -bc /etc/nginx/.htpasswd admin gemini
+
+COPY nginx-proxy.conf /etc/nginx/nginx.conf