feat: implement auto-response throttling to limit execution frequency

src/auto_response/handler.rs

@@ -2,6 +2,7 @@
 
 use log::{debug, info};
 use poise::serenity_prelude::{Context, CreateMessage, Message as SerenityMessage};
+use rand::random;
 
 use crate::error::Result;
 
@@ -10,6 +11,10 @@ use super::{
     rules::{AutoResponsePayload, AutoResponseRule},
 };
 
+fn should_send_auto_response() -> bool {
+    random::<u32>().is_multiple_of(6)
+}
+
 /// Handle auto-responses for pre-configured match rules.
 ///
 /// Returns `true` if an auto-response was sent, `false` otherwise.
@@ -34,6 +39,16 @@ pub async fn handle_auto_response(
         return Ok(false);
     };
 
+    if !should_send_auto_response() {
+        debug!(
+            "Auto response throttle: skipped rule '{}' for {} in channel {}",
+            action.rule_name,
+            new_message.author.tag(),
+            new_message.channel_id
+        );
+        return Ok(false);
+    }
+
     let AutoResponsePayload::ImageUrl(content) = action.payload;
 
     let message = CreateMessage::new()