Verify events.watch max TTL and privateExtendedProperty AND/OR

Two items still flagged as unverified in the specification, both only mattering once the return path exists.

- [ ] **Max TTL for `events.watch`.** Measure the actual `expiration` returned; adjust the daily renewal cadence if it is shorter than 7 days.
- [ ] **Whether repeated `privateExtendedProperty` filters are AND or OR.** Google's reference and guide contradict each other. Test both; record the answer here. Only relevant if Orrey ever filters by extended property (the syncToken constraint means it currently does not).

Start by checking whether the return path for events.watch exists, then consult Google's reference and guide. Measure the expiration returned by events.watch and test repeated privateExtendedProperty filters for AND versus OR behavior; document the TTL and filter result here, including whether the renewal cadence needs adjustment.

Rédigé par le modèle d'indexation à partir du texte de l'issue.