Fix /perfil upload double-submit (button not disabled during await)

Follow-up to PLUTO-596 (ERR_DLOPEN sharp crash). Root cause of 109 hits in 5:40: profile-photo-upload.tsx Subir button's disabled was bound to useTransition isPending, but the transition only wrapped the post-success router.refresh(), not the await uploadProfileImage round-trip - button stayed enabled + no feedback during upload, so repeat-clicking on the failure toast fired concurrent submissions. Fixed with a busy in-flight lock covering the whole submit, button disabled + Subiendo... for full duration. documento path (perfil-editable.tsx) already correctly guarded, no change needed. SHA 75c9b3c v2.20.5, live-verified, Class-S self-verified.