Add Sensitivity Configuration

[pbalduino]

Description

Allow users to adjust microphone sensitivity for different environments

Priority

🟢 Low

Category

Settings

Details

• Add sensitivity slider in settings screen
• Implement sensitivity levels (Low, Medium, High)
• Adjust audio input gain based on sensitivity setting
• Provide visual feedback for current sensitivity level
• Save sensitivity preference to local storage

Files Affected

• lib/screens/settings_screen.dart
• lib/screens/tuner_screen.dart

Acceptance Criteria

• Sensitivity can be adjusted from settings
• Different sensitivity levels work as expected
• Setting affects audio input processing
• Preference is saved and persisted
• Visual feedback shows current level

Task ID: SETTINGS-001