Create Unique URLs for Restaurants in CodeIgniter SaaS

Project Overview:
I own a multi-restaurant SaaS POS system built on:
- PHP (CodeIgniter MVC)
- PHP 8.x / MySQL 8.x
- JavaScript + jQuery
- Bootstrap
- HTML/CSS
- PWA support
- Print library: mike42/escpos-php
- Print Server: XAMPP bridge

I also have a single-restaurant version of the software, where each restaurant gets a fully functional public website:
- Home Page (slideshow, featured items, map)
- About Us page
- Online Order (menu with images, prices, descriptions)
- Contact Page
- Cart + Checkout
- Admin/Customer login

This version works perfectly.

However, in the SaaS version, all restaurants share ONE website, forcing customers to:
1. Visit a single shared URL
2. Choose a restaurant from a list of many (sometimes 50+)
3. Then navigate again to its home page
4. Then click Online Order again
5. Finally reach the menu
This UX is not acceptable and makes the SaaS version extremely inconvenient.

Current Problem in SaaS Version:
- No unique link for each restaurant
- Customers see all restaurants from different countries
- Restaurants cannot share a direct link or QR code to their online menu
- Customers must search for their restaurant inside a big list
- Restaurants in Dubai can see restaurants in Lebanon, etc. (not logical)

What I Need (Required Work):
Create a proper multi-tenant routing structure so each restaurant in the SaaS has its own direct public website & menu URL, similar to the single-installation version.

Option 1 (Preferred): Path-Based URLs
Example:
https://mydomain.com/r/restaurant-slug
https://mydomain.com/r/restaurant-slug/menu
https://mydomain.com/r/restaurant-slug/about
https://mydomain.com/r/restaurant-slug/cart

Option 2 (Optional, quote separately): Subdomain Support:
https://restaurant-slug.mydomain.com

What the system must do:
- Each restaurant has a unique slug stored in the DB.
- Public website loads automatically based on the slug.
- All content (home, about, contact, menu, cart) filtered by restaurant_id.
- Completely remove the “choose restaurant” step from the customer flow.
- Prevent customers from accessing another restaurant by mistake.
- Generate a QR code per restaurant (URL provided in dashboard).
- Keep using the same codebase (no duplication).

Deliverables
✔ Update CodeIgniter routes to support restaurant slugs
✔ Modify public-facing controllers to load restaurant data using slug
✔ Update menu/about/contact/cart pages to filter by restaurant
✔ Fix all URLs inside the views to include slug
✔ Add QR link field inside restaurant dashboard
✔ Clean, secure, well-tested solution
✔ Full instructions on deployment (routes, .htaccess, or Nginx config)

(If subdomains option is selected)
✔ Wildcard subdomain logic
✔ detect restaurant by subdomain
✔ fallback for path-based URLs

What You Should Know (Technical Stack)
- PHP 8.x
- MySQL 8.x
- CodeIgniter (MVC) — required
- Bootstrap
- jQuery
- JSON
- REST
- PWA basics (optional)

Files & Folder Structure of the SaaS POS platform:
The app includes standard CodeIgniter MVC folders:
/application
/system
/assets
/vendor
/uploads
/index.php
...etc

Ideal Developer Must Have:
- Very strong CodeIgniter experience (CI3 or CI4)
- Multi-tenant / SaaS experience
- Understanding of routing + slug-based systems
- Clean coding practices
- Ability to work inside an existing complex POS system
- Good communication and fast delivery

Budget:
- Please propose your best fixed price.
The original developer quoted a very high price.
I expect reasonable offers depending on your experience.

Important Notes:
- I will provide full source code + database copy
- You will be working on a staging VPS
- No changes to POS core features — only public-facing website routing
- Looking for a fast, clean, production-safe implementation

Documentation Requirement (Mandatory)
All changes to existing files must be:
- Well-documented
- Listed clearly in a change log
- Described line-by-line or section-by-section
- Explained why they were needed
- Searchable (e.g., “added code is marked with // SaaS-Slug-Start and // SaaS-Slug-End”)
- Marked code blocks inside each modified file, like:
// SaaS-Slug-Start
// new routing logic for restaurant slug
...
// SaaS-Slug-End

The developer must provide:
A text file or PDF listing:
- File name
- File path
- Lines modified
- Purpose of the modification

To Apply, Answer These:
1. Have you built multi-tenant systems before?
2. Can you share CodeIgniter projects you worked on?
3. Do you prefer path-based URLs or subdomains? Why?
4. Estimated time to complete?
5. Best fixed price?