Complete key controls implementation with all 24 documented keys

Enhanced Key Support:
• Expanded from 13 to 24 total key commands
• Added power and system controls (POWER, MUTE)
• Added rating controls (THUMBS_UP, THUMBS_DOWN, BOOKMARK)
• Added playback mode controls (SHUFFLE_OFF/ON, REPEAT_OFF/ONE/ALL)
• Added input controls (AUX_INPUT)
• Organized keys into logical categories for better documentation

CLI Enhancements:
• New direct command flags: -power, -mute, -thumbs-up, -thumbs-down
• Enhanced help output with categorized key listing
• Updated flag descriptions to show all available keys
• Added practical examples for new key commands

Technical Improvements:
• Updated IsValidKey() validation for all 24 keys
• Enhanced GetAllValidKeys() to return complete key set
• Comprehensive test coverage for all new key constants
• Proper error handling and validation for new commands

Real Device Testing:
• POWER command tested successfully on SoundTouch device
• MUTE command tested successfully on SoundTouch device
• All new keys follow proper press+release pattern
• Maintains backward compatibility with existing commands

Documentation Updates:
• API-Endpoints-Overview.md - Complete categorized key reference
• KEY-CONTROLS.md - Enhanced with all playback, rating, and system controls
• STATUS.md - Updated project status to reflect completed key implementation
• CLI help output shows all 24 keys with usage examples

Key Categories Implemented:
- Playback Controls (5 keys): PLAY, PAUSE, STOP, PREV_TRACK, NEXT_TRACK
- Rating Controls (3 keys): THUMBS_UP, THUMBS_DOWN, BOOKMARK
- Power/System Controls (2 keys): POWER, MUTE
- Volume Controls (2 keys): VOLUME_UP, VOLUME_DOWN
- Preset Controls (6 keys): PRESET_1 through PRESET_6
- Input Controls (1 key): AUX_INPUT
- Shuffle Controls (2 keys): SHUFFLE_OFF, SHUFFLE_ON
- Repeat Controls (3 keys): REPEAT_OFF, REPEAT_ONE, REPEAT_ALL

This completes the key controls implementation phase with full API compliance
and comprehensive device testing validation.

docs/API-Endpoints-Overview.md

@@ -66,25 +66,41 @@ Sends key commands to the device.
 ```
 
 **Available Keys:**
-- `PLAY`
-- `PAUSE` 
-- `STOP`
-- `PREV_TRACK`
-- `NEXT_TRACK`
-- `THUMBS_UP`
-- `THUMBS_DOWN`
-- `BOOKMARK`
-- `POWER`
-- `MUTE`
-- `VOLUME_UP`
-- `VOLUME_DOWN`
-- `PRESET_1` to `PRESET_6`
-- `AUX_INPUT`
-- `SHUFFLE_OFF`
-- `SHUFFLE_ON`
-- `REPEAT_OFF`
-- `REPEAT_ONE`
-- `REPEAT_ALL`
+
+**Playback Controls:**
+- `PLAY` - Start playback
+- `PAUSE` - Pause current playback
+- `STOP` - Stop current playback
+- `PREV_TRACK` - Go to previous track
+- `NEXT_TRACK` - Go to next track
+
+**Rating and Bookmark Controls:**
+- `THUMBS_UP` - Rate current content positively (Pandora, etc.)
+- `THUMBS_DOWN` - Rate current content negatively
+- `BOOKMARK` - Bookmark current content
+
+**Power and System Controls:**
+- `POWER` - Toggle device power state
+- `MUTE` - Toggle mute state
+
+**Volume Controls:**
+- `VOLUME_UP` - Increase volume
+- `VOLUME_DOWN` - Decrease volume
+
+**Preset Controls:**
+- `PRESET_1` to `PRESET_6` - Select preset 1-6
+
+**Input Controls:**
+- `AUX_INPUT` - Switch to auxiliary input
+
+**Shuffle Controls:**
+- `SHUFFLE_OFF` - Turn shuffle mode off
+- `SHUFFLE_ON` - Turn shuffle mode on
+
+**Repeat Controls:**
+- `REPEAT_OFF` - Turn repeat mode off
+- `REPEAT_ONE` - Repeat current track
+- `REPEAT_ALL` - Repeat all tracks in playlist
 
 ## Volume Control