Frame age p95 and bytes per viewer for H.264 versus MJPEG are measured on the public URL and written in the README #403

Replaces #263 unchanged in scope; it waited on #260, which was split into #382 and #383. It now waits on #383, the page playing H.264, which is what it measures.

Done:

• [ ] With the Pi renditions running and the H.264 page live, the frame age p95 (capture to shown) is measured on home wifi and on 4G, along with any freezes in 10 minutes and the bytes per viewer for H.264 against MJPEG. The numbers and how they were taken go in Software/README.md.
• [ ] Targets: p95 under 250 ms on wifi and under 500 ms on 4G, with 0 freezes. A target that is missed is written down as missed, not hidden.

Parked by the crew: the run ended without a pull: declined: this issue asks for numbers taken by a person with real hardware, and I can't take them from here. The frame age p95 (capture to shown) has to be measured on home wifi and on 4G with the Pi renditions

Steward (a person): left assigned without a pull, holding the arm crew. Unassigned so any builder starts it fresh from main.

Closed: already done on main in 2bd01031 (pull #431).