feat: add /reasoning reasoning visibility

src/auto-reply/thinking.ts

@@ -1,6 +1,7 @@
 export type ThinkLevel = "off" | "minimal" | "low" | "medium" | "high";
 export type VerboseLevel = "off" | "on";
 export type ElevatedLevel = "off" | "on";
+export type ReasoningLevel = "off" | "on";
 
 // Normalize user-provided thinking level strings to the canonical enum.
 export function normalizeThinkLevel(
@@ -55,3 +56,31 @@ export function normalizeElevatedLevel(
   if (["on", "true", "yes", "1"].includes(key)) return "on";
   return undefined;
 }
+
+// Normalize reasoning visibility flags used to toggle reasoning exposure.
+export function normalizeReasoningLevel(
+  raw?: string | null,
+): ReasoningLevel | undefined {
+  if (!raw) return undefined;
+  const key = raw.toLowerCase();
+  if (
+    [
+      "off",
+      "false",
+      "no",
+      "0",
+      "hide",
+      "hidden",
+      "disable",
+      "disabled",
+    ].includes(key)
+  )
+    return "off";
+  if (
+    ["on", "true", "yes", "1", "show", "visible", "enable", "enabled"].includes(
+      key,
+    )
+  )
+    return "on";
+  return undefined;
+}