Add interactive string interop example with ownership and user flow

[shashu8660]

This PR adds an interactive string interoperability example between Rust and C++.

The example demonstrates:

• Passing strings from C++ to Rust using const char*
• Returning strings from Rust to C++ using CString
• Ownership transfer across the FFI boundary (Move, Forget, Own)
• Safe memory management and explicit deallocation
• Interactive user input flow

The example includes:

• Rust library exposing FFI functions
• C++ program handling user input and interaction
• run.sh script for building and running the example

This aligns with the string interop problem https://github.com/rustfoundation/interop-initiative/blob/main/problem-space/0002-string-interop.md & demonstrates safe handling of string ownership and memory across language boundaries

[teor2345]

Hi, I've already looked at your PR #30, we're just going to focus on one PR per person for now. After that PR is finished, we can decide what to do with this one.

[teor2345]

This is a good example, but let's shorten or remove the documentation file, and name it README.md

[teor2345]

This file isn't a problem statement, it is a description of the example.

We don't need something this long to describe an example, please summarise what the example does. It is also ok to delete this file and just write a short README.md

[teor2345]

You'll also have to resolve conflicts, I think rebasing or squashing the PR should do it.

[shashu8660]

updated the readme.md

[teor2345]

Thank you! Let's merge if it passes CI.

The merge-base changed after approval.

[teor2345]

You'll also have to resolve conflicts, I think rebasing or squashing the PR should do it.

Please squash the PR.

Some commits contain files in the examples/rust-cpp-basic-interop directory, which already exists in the main branch. Those commits will disappear when you squash.

I can help with this if you need it?

[shashu8660]

I done it , do I need to do any other changes

[teor2345]

Looks like maybe you accidentally deleted a bunch of changes you just made, rather than squashing them?

The code and docs you had in the previous commits were fine, we just need to combine all the commits into a single commit.

[shashu8660]

Is there anything else do I need to change or any update ?

[teor2345]

When you tried to squash, you deleted some files from other examples, and reversed some changes in your previous commits. Don't do that.

Instead, go back to your previous branch, and squash the commits together using git rebase --interactive, and replace "pick" with "squash" in the list.

[shashu8660]

Thank you for pointing out the mistake I was making @teor2345 ,
It was a new topic for me in git which I have never used before so

[teor2345]

Thanks!

I've deleted the .gitignore file because there's already one in the repository base directory.

Let's merge!

[teor2345]

New changes require approval from someone other than teor2345 because they were the last pusher.

It's just a redundant file deletion, so I'm going to override this and merge,