Add status bar UI and Gemini AI provider support

[kilabyte]

🎯 AI Provider Updates:

• Replace Ollama/OpenRouter with Google Gemini provider (full audio transcription + text generation)
• Update OpenAI model list with latest GPT-5, GPT-4.5, GPT-4.1 variants
• Implement provider factory pattern for easy switching between OpenAI and Gemini
• Add provider-specific settings UI with dynamic model selection

🎙️ Status Bar Recording Interface:

• Add non-intrusive status bar recording that doesn't block workflow
• Implement "Remember Target Note" feature with three modes:
  • Always remember current note (auto-append to bottom)
  • Ask each time (confirmation dialog)
  • Never remember (insert at cursor position)
• Add configurable status bar positioning (far-left, left, center, right, far-right)
• Proper DOM insertion with cleanup to prevent duplicate elements

🎨 UI/UX Improvements:

• Streamline status bar controls (remove "Stop Only" button)
• Icon-only buttons with descriptive tooltips
• Visual indicator when recording to target note (blue timer)
• Clean record/pause workflow with "Stop & Transcribe" action

🧠 Smart Transcription Logic:

• Append transcriptions to bottom of target notes (preserves existing content)
• Maintain cursor-position behavior for normal transcription
• Target note persistence even when navigating away during recording
• Smart note opening/switching for seamless workflow

🔧 Technical Enhancements:

• Fix status bar initialization and settings propagation
• Proper TypeScript typing for App and component interfaces
• Real-time settings updates without plugin restart
• Improved error handling and debug logging

📖 Documentation:

• Update README with all new features
• Maintain original content structure
• Add clear usage instructions for new functionality