feat: implement secure multi-tenancy, RBAC, and premium dark mode

- Enforced tenant isolation and Role-Based Access Control across all API routes

- Implemented secure profile avatar upload using multer and UUIDs

- Redesigned UI with a premium "Onyx & Gold" Charcoal dark mode

- Added Funnel Stage and Origin filters to Dashboard and User Detail pages

- Replaced "Referral" with "Indicação" across the platform and database

- Optimized Dockerfile and local environment setup for reliable deployments

- Fixed frontend syntax errors and improved KPI/Chart visualizations

Dockerfile

@@ -4,9 +4,6 @@ FROM node:22-alpine AS builder
 WORKDIR /app
 
 COPY package.json ./
-# In a real scenario, copy package-lock.json too
-# COPY package-lock.json ./
-
 RUN npm install
 
 COPY . .
@@ -20,18 +17,19 @@ WORKDIR /app
 
 ENV NODE_ENV=production
 
-COPY package.json ./
-COPY backend/package.json ./backend/
+# Copy backend package.json as main package.json
+COPY backend/package.json ./package.json
 
-# Install dependencies (including production deps for backend)
+# Install dependencies
 RUN npm install --omit=dev
 
-# Copy backend source
-COPY backend/ ./backend/
+# Copy backend source directly into root
+COPY backend/index.js ./index.js
+COPY backend/db.js ./db.js
 
-# Copy built frontend from builder stage
+# Copy built frontend
 COPY --from=builder /app/dist ./dist
 
 EXPOSE 3001
 
-CMD ["node", "backend/index.js"]
+CMD ["node", "index.js"]