64 save diagrams in server

[egenerse]

Checklist

• I linked PR with a related issue
• I added multiple screenshots/screencasts of my UI changes

Motivation and Context

This PR completes #64

Description

Environment variables are used to increase port/host flexibility
this pr merges to share modal
New env variables are defined for handling connections
Standalone server side has typescript and javascript
A new router is created in server to get and set diagrams in persistence db
Keep server.ts simple

Steps for Testing

Create .env files for standalone/webapp and standalone/server. Check .env.examples files and create values
Create a diagram locally and edit it.
Click share in the navbar and select any option from there.
You should see a new toast message on the right side
Check if the URL is copied to your clipboard by pasting it any text
Open the share modal and recopy the URL anytime to share with other users

Screenshots

Screen.Recording.2025-04-04.at.17.59.12.mov

Screen.Recording.2025-04-04.at.18.16.17.mov

[kurunbelemir]

I couldnt create collaboration link when I clicked the button. Am I missing something in the setup?

[kurunbelemir]

I still have same issue after I created .env file and build an run.

[kurunbelemir]

After I created the .env files, everthing works.
Endpoints are tested with postman.
Good work.