SCRIPT.md: VO pacing and writing rules

VO for every video should sound like the same person wrote it: direct, confident about what's actually shown, never claiming more than the visual backs up.

Pace

Target ~2.3-2.9 words/sec. This is edge-tts's natural reading pace at default settings, the actual ratio observed across this pipeline's production use, not a theoretical number. If you're writing VO for a beat of known duration, word-count budget equals duration_seconds * pace; stay inside that range rather than writing to a "feels about right" length and hoping it fits.

Duration formula

When a beat's duration is being derived from its VO (rather than the other way around):

duration = (VO word count / pace) + pad

Use a pad of 0.3-0.6s. The pad exists so the visual doesn't cut the instant speech ends: a beat that ends exactly when the last word does reads as clipped, and a small buffer lets the shot breathe for a moment before the cut.

The claim-obligates-visual rule

If a beat's VO asserts the product does something, the visual must back it up: either a real capture (screenshot/recording) of the product actually doing it, or an explicitly labeled dom-demo mockup built for a feature that isn't wired up yet. Never let VO overclaim past what's on screen. If the visual can't back a sentence, rewrite the sentence, don't leave it in and hope no one checks.

This is the same rule PIPELINE.md states for beat authoring generally; here it's specifically about VO, because VO is usually written first and is where an overclaim first gets introduced. Use PLANNING.md's per-feature capture-method decision tree to decide, for each claim, whether it needs a real capture or an honest dom-demo. Don't write a claim the decision tree can't resolve to something real or explicitly-labeled-constructed.

No em dashes

No em dashes in any VO line, ever, same writing rule as every other doc in this pipeline. Use commas, periods, or a rewritten sentence instead.