feat: context isolation support and robust IPC (issue #337)

[4rayaditya]

This PR refactors the SDK to fully support Electron’s context isolation, following modern security best practices. It introduces a preload script, secure IPC handlers, and a clear integration pattern for all SDK features.

Key Changes

Context Isolation Ready:

• All SDK APIs are now exposed to the renderer via [preload.js] using [contextBridge].
• No direct Node.js/Electron access from the renderer; all communication is via IPC.

Main Process IPC Handlers:

• Added [electron-sdk-ipc.js] to handle all SDK feature requests (screen sharing, remote control, always-on-top) securely in the main process.
• Real always-on-top window logic and logging for visible testing and debugging.

Example Integration:

• Provided a minimal test app and renderer example (not included in final commit unless requested) to demonstrate and verify the new integration pattern.

Bug Fixes & Lint:

• Fixed all import, constructor, and lint errors.
• Codebase passes all lint checks.

Testing

• Verified all features work with context isolation enabled.
• Manual test app demonstrates successful IPC and UI integration.
• Terminal logs confirm handler activity.

[4rayaditya]

@damencho @saghul I have tried to address the issue #337 through this PR. Please check.

[saghul]

Thanks for getting this started @4rayaditya !

We are in the process of refactoring the SDK to deal with some Electron 38 changes, so alas we cannot take these changes as they are today.

We'll get back to this issue in due time.