perf(help.py): cache prefixes to reduce redundant fetch operations

Cache prefixes for each guild to improve performance by minimizing
repeated fetch operations. This change reduces the overhead of
dynamically fetching prefixes, especially in environments with
multiple guilds.

tux/help.py

@@ -26,11 +26,17 @@ def __init__(self):
                 "usage": "$help <command> or <sub-command>",
             },
         )
+        self._prefix_cache: dict[int | None, str] = {}
 
-    # Helpers for Prefix and Embeds
     async def _get_prefix(self) -> str:
-        """Dynamically fetches the prefix from the context or uses a default prefix."""
-        return self.context.clean_prefix or CONFIG.DEFAULT_PREFIX
+        """Fetches and caches the prefix for each guild."""
+        guild_id = self.context.guild.id if self.context.guild else None
+
+        if guild_id not in self._prefix_cache:
+            # Fetch and cache the prefix specific to the guild
+            self._prefix_cache[guild_id] = self.context.clean_prefix or CONFIG.DEFAULT_PREFIX
+
+        return self._prefix_cache[guild_id]
 
     def _embed_base(self, title: str, description: str | None = None) -> discord.Embed:
         """Creates a base embed with uniform styling."""