feat: integrate Sensei Spook mascot in 4 stances, speech bubbles, and style updates

lib/ai/safety.ts

@@ -0,0 +1,28 @@
+export class ContentSafetyError extends Error {
+  public readonly isSafetyRejection = true;
+
+  constructor(message: string) {
+    super(message);
+    this.name = "ContentSafetyError";
+    Object.setPrototypeOf(this, ContentSafetyError.prototype);
+  }
+}
+
+export function isContentSafetyError(err: any): boolean {
+  if (!err) return false;
+  if (err.isSafetyRejection || err.name === "ContentSafetyError") return true;
+
+  const msg = String(err.message || err.error || err || "").toLowerCase();
+  return (
+    msg.includes("safety filter") ||
+    msg.includes("prohibited_content") ||
+    msg.includes("harm_category") ||
+    msg.includes("safe-for-work") ||
+    msg.includes("finishreason: safety") ||
+    msg.includes("finishreason: blocklist") ||
+    msg.includes("blockreason") ||
+    msg.includes("content safety") ||
+    msg.includes("safety policy") ||
+    msg.includes("violates safety")
+  );
+}