feat: Add comprehensive backend validation, toast notifications, and Tokyo Night theme

- Backend: Add server-side validation with go-playground/validator/v10
- Frontend: Add toast notifications for API errors with @zerodevx/svelte-toast
- UI: Complete Tokyo Night theme redesign with modern animations
- Docs: Update COMPLETE_DOCUMENTATION.md and README.md with all enhancements
- Validation: Email format, password strength, and input sanitization
- UX: Real-time error feedback, loading states, and responsive design

backend/Dockerfile

@@ -0,0 +1,58 @@
+# Build stage
+FROM golang:1.25-alpine AS builder
+
+WORKDIR /app
+
+# Install Node.js and npm
+RUN apk add --no-cache nodejs npm
+
+# Install sqlc
+RUN go install github.com/sqlc-dev/sqlc/cmd/sqlc@latest
+
+
+
+# Copy backend source code
+COPY backend/ ./backend/
+
+# Copy frontend source for building
+COPY frontend/package*.json ./frontend/
+WORKDIR /app/frontend
+
+# Install frontend dependencies (cached if package.json unchanged)
+RUN npm ci
+
+# Copy frontend source
+COPY frontend/ ./
+
+# Build frontend
+RUN npm run build
+
+# Go back to root
+WORKDIR /app
+
+# Generate sqlc code
+RUN cd backend && sqlc generate
+
+# Build the application
+RUN cd backend && CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o ../main ./cmd/server
+
+# Final stage
+FROM alpine:latest
+
+RUN apk --no-cache add ca-certificates
+WORKDIR /root/
+
+# Copy the binary from builder stage
+COPY --from=builder /app/main .
+
+# Copy migrations (if needed for initialization)
+COPY --from=builder /app/backend/migrations ./migrations
+
+# Copy static files
+COPY --from=builder /app/frontend/build ./static
+
+# Expose port
+EXPOSE 8080
+
+# Run the binary
+CMD ["./main"]