🧩 Implement real context switching between processes (64 bit)

[IRodriguez13]

• The kernel currently simulates process switching but does not perform actual context switches. process_switch() is a placeholder.

To enable multitasking:

• Save/restore full register context (RAX–R15, segment registers, flags)

• Switch page tables if needed

• Handle kernel/user transitions

• Integrate with scheduler logic

• This is a core feature for enabling concurrent execution.

[IRodriguez13]

🛠 Contribution Reminder: To contribute to this issue, please follow these steps:

• Fork the upstream repository

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• Create a branch named feat/issue-name based on your fork.

• Make your changes and commit them to that branch.

• Open a pull request targeting the dev branch — never mainline.

This helps keep contributions organized and ensures stability in the mainline branch. Thanks for helping improve the kernel!