ytaudio: add [p]summon to join VC; revert tts join change

Add a summon command (alias ytjoin) that joins the caller's voice
channel, replacing the old Audio-cog summon. _ensure_connected now
moves the bot with Player.move_to when it is already in a different
channel. Revert the ttstoy tts join back to the simple connect.

ttstoy/ttstoy.py

@@ -2434,21 +2434,12 @@ class TtsToy(Cog):
             # Check if user is in a VC - we'll play there if so, but it's not required
             user_in_vc = ctx.author.voice and ctx.author.voice.channel
 
-            if user_in_vc:
-                target_channel = ctx.author.voice.channel
-                me_voice = ctx.guild.me.voice
-                # Summon: connect if not in voice, or move if in a different channel.
-                if me_voice is None or me_voice.channel is None:
-                    try:
-                        await lavalink.connect(target_channel)
-                    except Exception:
-                        log.exception("[TTS] Failed to connect to voice channel via Lavalink.")
-                elif me_voice.channel.id != target_channel.id:
-                    try:
-                        player = lavalink.get_player(ctx.guild.id)
-                        await player.move_to(target_channel)
-                    except Exception:
-                        log.exception("[TTS] Failed to move to the user's voice channel.")
+            if user_in_vc and not ctx.guild.me.voice:
+                # Connect via the shared Lavalink client (owned by the YTAudio cog).
+                try:
+                    await lavalink.connect(ctx.author.voice.channel)
+                except Exception:
+                    log.exception("[TTS] Failed to connect to voice channel via Lavalink.")
 
             mode = await self._get_tts_mode()