VPS Setup & PHP Customization for Webmail

Need to setup of VPS server and PHP customization:
hostname : xxxxxxxxx.com
domain : xxxxxxxxxxx.com

required to have one live (www.xxxxxxx.com) and one devlopment site (www.dev.xxxxxxxxx.com)

swap memeory of 6 GB

Need to setup my VPS with Ubuntu 24.04 LTS + Pure Nginx
Need to Install PostgreSQL 18
Need to Instal Roundcube webmail + converse.js
Requirement :
Custom XMPP/Converse.js Integration for Roundcube (Gmail-style Sidebar & Fullscreen UI)

Project Overview:
We are looking for an experienced PHP/JavaScript developer to integrate an XMPP chat client (Converse.js) into our Roundcube Webmail (Elastic skin). The goal is to replicate the Google Chat user experience within Gmail, where chat is a primary sidebar task that, when selected, takes over the main viewing area in a fullscreen, professional, corporate layout.

Technical Requirements & Scope :
Roundcube Sidebar Integration
Add a custom Chat button to the Roundcube left-hand vertical navigation menu (Taskbar).

The button must use a custom SVG icon (Google Chat style).

Implement a "Task" switcher: When the Chat button is clicked, the Mail panels should be hidden, and the Converse.js fullscreen interface should be displayed in the main content area.

Converse.js Configuration (Corporate/Google Style)
View Mode: Must be set to fullscreen or embedded (not overlay boxes).

Authentication: Implement XMPP Pre-binding via PHP. Users must be automatically logged into the chat server using their Roundcube session/credentials (SSO).

UI Customization:

Match the "Elastic" Roundcube theme.

Apply a Corporate/Flat UI (remove shadows, gradients, and rounded chat bubbles).

Primary color palette must be customizable via CSS variables (SASS/SCSS preferred).

Features to Enable: Multi-user chat (MUC), file uploads (XEP-0363), chat history (MAM), and delivery receipts.


Performance & Backend
Transport: Configure the client to use WebSockets (WSS) instead of BOSH for lower latency.

Responsiveness: The layout must be fully responsive, working seamlessly on mobile and tablet views within the Roundcube Elastic skin.

screening question : "Have you ever implemented XMPP pre-binding in a PHP environment?" This filters out generic bidders.

requirement:
mail.xxxxxxxx.com should redirect to xxxxxxxxx.com/webmail but the URL should be shown to user is xxxxxxxx.com
webmail.xxxxxxx.com should redirect to xxxxxxxx.com/webmail but the URL should be shown to user is xxxxxx.com
admin.xxxxxxxxxx.com should redirect to xxxxxxx.com/10000 but the URL should be shown to user is xxxxxxxxx.com
usermin.xxxxxxxx.com should redirect to xxxxxxx.com/20000 but the URL should be shown to user is xxxxxxx.com

users :
webadmin

Location:
webadmin:/home/tag/public_html/
/home/dev/public_html/
webadmin:/home/webmail (central location. so that can use for multiple locations)


NOTE: We have 1 hr for the setup and 1 day for the customization.