Playbook: fix a weak reel hook in 3 metrics

Playbook: fix a weak reel hook in 3 metrics
Reels losing 50% of viewers by 3 seconds cap at 1.4x average reach (n=320 reels, 45-day window). The hook is measurable.
—
Read the 3-second retention bar in insights — under 50% means re-shoot the open.
—
Check the watch-curve shape: cliff = bad hook, slow slope = bad pacing.
—
Log re-watch percentage; over 100% total view time signals loop-worthy structure.
3-sec retention by reach tier:
Low-reach: ███ 41% | Median: █████ 58% | Viral: ████████ 79%
So what: 3-second retention is the gatekeeper metric. Distribution scales with it almost linearly until ~70%.