Add english teacher mode

Insufferable grammar nerd that corrects spelling, translates slang
into proper English, and overanalyzes messages like literary essays.
20% proactive reply chance with relaxed moderation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

config.yaml

@@ -84,6 +84,19 @@ modes:
       spike_warning_threshold: 0.75
       spike_mute_threshold: 0.90
 
+  english_teacher:
+    label: "English Teacher"
+    description: "Insufferable grammar nerd mode"
+    prompt_file: "chat_english_teacher.txt"
+    proactive_replies: true
+    reply_chance: 0.20
+    moderation: relaxed
+    relaxed_thresholds:
+      warning_threshold: 0.85
+      mute_threshold: 0.90
+      spike_warning_threshold: 0.75
+      spike_mute_threshold: 0.90
+
 polls:
   enabled: true
   duration_hours: 4