Remove allowedSfxChannels functionality - allow SFX in all channels

- Remove allowedSfxChannels from database schema and all code
- Remove channel checking logic from all SFX commands (!sfx, /sfx, /soundboard)
- Remove /config sfxchannels subcommand
- Update config.json and example to remove channel restrictions
- Simplify SFX system to work in any channel with bot access

Benefits:
- Better user experience - no confusing channel restrictions
- Simpler configuration - fewer settings to manage
- Cleaner codebase - reduced complexity
- Universal access - SFX works anywhere the bot can send messages

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/commands/slash/sfx.js

@@ -14,17 +14,6 @@ module.exports = {
     ),
 
   async execute(interaction, guildConfig) {
-    // Check if SFX is allowed in this channel
-    if (guildConfig.allowedSfxChannels) {
-      const allowedChannels = new RegExp(guildConfig.allowedSfxChannels);
-      if (!allowedChannels.test(interaction.channel.name)) {
-        return interaction.reply({ 
-          content: 'Sound effects are not allowed in this channel!', 
-          flags: [MessageFlags.Ephemeral]
-        });
-      }
-    }
-
     const sfxName = interaction.options.getString('sound');
 
     // Check if user is in a voice channel