feat: add client-driven session support with AgentLoop

[JacobFV]

• Add AgentSessionType for desktop, android, quantum session types
• Add step() method to SessionsResource for client-driven execution
• Add listModels() method with optional filter parameter
• Add AgentLoop class for async event loop management
  • Supports start/pause/resume/stop control
  • Callbacks for screenshot capture, action execution, thinking
• Add DesktopAction, StepDesktopResponse, ModelsResponse types
• Add requestUrl() to HTTPClient for arbitrary URL requests
• Update README with client-driven sessions documentation
• Add test script for integration testing

Co-Authored-By: Claude Opus 4.5 noreply@anthropic.com

Description

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code refactoring
• Performance improvement
• Test improvement

Related Issues

Closes #
Fixes #
Relates to #

Changes Made

• Change 1
• Change 2
• Change 3

Testing

Test Plan

• All existing tests pass (npm test)
• Added new tests for new functionality
• Tested manually in development environment
• Tested with different Node.js versions (if applicable)

Test Commands Run

npm run build
npm test
npm run lint
npm run typecheck

Screenshots (if applicable)

Checklist

Code Quality

• Code follows the project's style guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Lint passes (npm run lint)
• Type checking passes (npm run typecheck)

Testing

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally (npm test)
• I have tested the changes manually

Documentation

• I have updated the README.md (if applicable)
• I have updated the CHANGELOG.md
• I have added/updated JSDoc comments for public APIs
• I have updated examples (if applicable)

Git

• My commits follow the project's commit message conventions
• I have rebased/merged from the latest main branch
• My branch is up to date with the main branch

Breaking Changes

Before:

// Old API

After:

// New API

Migration Guide (if applicable)

Additional Notes

Reviewer Notes

[NamanGarg20]

LGTM