v1.68.0

Added

• product.<slot>.pricePerDay / pricePerDayAmount — the per-day price, exposed at last. deriveProductFields already computed perDay(p) and derived week/month/year and savingsPct from it, then discarded the value itself, so the per-day framing that anchors most trial paywalls ("$0.43 / day" beside "$39.99 / quarter") could not be authored at all despite the number existing. Projected as a flat dotted variable like its siblings and covered by the exhaustive key-list test.

Notes

• Absent whenever the period is unparseable, exactly like pricePerWeek/Month/Year — perDay needs a period. That matters because the failure is indistinguishable from "the feature did not ship": a product resolved without a period (or, in the studio editor's indicative preview, a catalog row with no duration_iso) yields an empty string rather than an error. There is a test pinning this.
• A misspelled product variable fails silently. interpolate renders an unknown {{key}} as an EMPTY STRING, never as the literal template, so {{product.yearly.pricePerDya}} ships as a blank where a price should be and reads as a styling bug. Now that prices are authorable directly on RadioGroup/CheckboxGroup cards (1.67.1) that is the one authoring error that reaches production invisibly — called out in the compose-screen-builder skill.

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