Add Cursor CLI provider support

[shakecodeslikecray]

Description

Add support for Cursor CLI as an LLM provider.

Tasks

• Research Cursor CLI capabilities and API
• Create src/providers/adapters/cursor.ts
• Add detection in src/providers/detect.ts
• Add tests
• Update documentation

Acceptance Criteria

• Users with Cursor installed can use it as a provider
• Provider detection works correctly
• Bug scanning produces results comparable to claude-code