FEATURE: safeguard to avoid over triage (#626)

- a post can be triaged a maximum of twice a minute
- system can run a total of 60 triages a minute

Low defaults were picked to safeguard against any possible loops

This can be amended if required via hidden site settings.

config/settings.yml

@@ -358,3 +358,9 @@ discourse_ai:
   ai_bot_github_access_token:
     default: ""
     secret: true
+  ai_automation_max_triage_per_minute:
+    default: 60
+    hidden: true
+  ai_automation_max_triage_per_post_per_minute:
+    default: 2
+    hidden: true

discourse_automation/llm_triage.rb

@@ -53,6 +53,20 @@ if defined?(DiscourseAutomation)
       flag_post = fields.dig("flag_post", "value")
 
       begin
+        RateLimiter.new(
+          Discourse.system_user,
+          "llm_triage_#{post.id}",
+          SiteSetting.ai_automation_max_triage_per_post_per_minute,
+          1.minute,
+        ).performed!
+
+        RateLimiter.new(
+          Discourse.system_user,
+          "llm_triage",
+          SiteSetting.ai_automation_max_triage_per_minute,
+          1.minute,
+        ).performed!
+
         DiscourseAi::Automation::LlmTriage.handle(
           post: post,
           model: model,
@@ -66,7 +80,7 @@ if defined?(DiscourseAutomation)
           flag_post: flag_post,
         )
       rescue => e
-        Discourse.warn_exception(e, message: "llm_triage: failed to run inference")
+        Discourse.warn_exception(e, message: "llm_triage: skipped triage on post #{post.id}")
       end
     end
   end