FEATURE REQUEST: Allowing joining teams via invite link

### Is your feature request related to a problem?

- [x] Yes, it is related to a problem

### Describe the feature you'd like

## 🌟 Feature Description
Add a way to invite users to a team using a shareable link.
This should work alongside the existing team code system and make it easier for teams to add new members.

## 🔍 Problem Statement
Currently, users can join a team only by entering a team code during signup.
This works, but it is not very convenient when teams want to invite people frequently.

Sharing team codes manually can be confusing and slow, and there is no simple way to invite someone with just one click.

## 🎯 Expected Outcome
Team admins can generate a shareable invite link
Users can join a team using a valid invite link
Invalid or expired invite links do not work
Only authorized users can create invite links
Existing team code join flow continues to work as it does now

## 📷 Screenshots and Design Ideas
A simple “Invite Member” option can be added in team settings.
Clicking it can generate a link that users can copy or share.

No major UI changes are required.

## 📋 Additional Context
This feature is meant to improve team onboarding without changing the current flow.
Database-level security (RLS) should be used to make sure invite links are created and used safely.

### Record

- [x] I agree to follow this project's Code of Conduct
- [x] I want to work on implementing this feature