v0.2.3 — .rise for photos, .rvid for videos

Extension split

Following the .webp/.webm model — one family, two classes:

Extension	Media	OS routing
.rise	sealed image (JPEG/PNG bytes)	image viewers
.rvid	sealed video (playable MP4 bytes)	video players

• macOS UTIs: .rvid → org.rise.sealed-video (conforms public.mpeg-4)
• Windows registry: .rvid → PerceivedType = video
• Linux shared-mime-info: .rvid → video/mp4
• Daemons (macOS + Windows) now emit .rvid for video seals
• Spec: RISE-01 §2.1
• RISE-0.2.3.pkg — one-click macOS installer with the updated format registration