AI disclaimer: also on the cards and the results

The note now rides along with the content itself, not only with the
generation screens and the chat composer:

- Under every card in the study feed and in the review, mistakes and exam
  sessions (the activity slide's last element — below the card, and below
  the feedback panel once answered).
- On the results slides: the study results screen and the shared session
  results (review, mistakes, exam).

Navigation surfaces (library, deck lists, chat history, settings) still
carry no note — it belongs to the moment of generation and to the card
being answered, not to browsing (README decision 50 updated).

The phase-2 grading check now scopes its placement (the disclaimer right
under the graded box) since the same text legitimately appears several
times on a session page; three new checks cover the feed, the results
slide and the exam (59 checks). SW -> freezmo-v40.

components/StudyFeed.tsx

@@ -5,6 +5,7 @@ import Link from "next/link";
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 
 import { ActivityRenderer } from "@/components/activities";
+import { AiDisclaimer } from "@/components/AiDisclaimer";
 import { celebrate } from "@/lib/confetti";
 import { ApiError, generateDeck } from "@/lib/client-api";
 import { materialiseActivities } from "@/lib/deck-ops";
@@ -326,6 +327,7 @@ export function StudyFeed({ deck }: { deck: Deck }) {
                 onAnswered={(correct, meta) => handleAnswered(activity, correct, meta)}
                 onNext={() => goTo(activityIndex + 1)}
               />
+              <AiDisclaimer />
             </div>
           </section>
         ))}
@@ -350,6 +352,7 @@ export function StudyFeed({ deck }: { deck: Deck }) {
               regenerating={regenerating}
               regenerateError={regenerateError}
             />
+            <AiDisclaimer />
           </div>
         </section>
       </div>