feat(dares): optional photo/audio proof of completion

The sender can require photo or audio proof when sending any dare,
catalogue or custom. The recipient captures and uploads the proof as a
new couple-scoped 'dare_proof' media kind and attaches it on submit;
the server enforces ownership, kind, couple, and MIME-type match.
The proof renders inline on the dare card for the sender to review
before confirming completion.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

apps/mobile/src/features/dares/hooks/useDares.ts

@@ -30,7 +30,7 @@ export interface UseDaresReturn {
     refresh: () => Promise<void>;
     send: (payload: SendDarePayload) => Promise<boolean>;
     respond: (dareId: string, action: "accept" | "decline") => Promise<void>;
-    submit: (dareId: string) => Promise<void>;
+    submit: (dareId: string, proofMediaId?: string) => Promise<void>;
     complete: (dareId: string) => Promise<void>;
     cancel: (dareId: string) => Promise<void>;
 }
@@ -167,7 +167,7 @@ export function useDares({ isFocused = true }: UseDaresConfig = {}): UseDaresRet
         refresh,
         send,
         respond: useCallback((dareId, action) => act(dareId, () => daresApi.respond(dareId, action)), [act]),
-        submit: useCallback((dareId) => act(dareId, () => daresApi.submit(dareId)), [act]),
+        submit: useCallback((dareId, proofMediaId) => act(dareId, () => daresApi.submit(dareId, proofMediaId)), [act]),
         complete: useCallback((dareId) => act(dareId, () => daresApi.complete(dareId)), [act]),
         cancel: useCallback((dareId) => act(dareId, () => daresApi.cancel(dareId)), [act]),
     };