Proton apps should offer consistent functionality across mobile, desktop, and the web. Currently, several important actions are only available in one version, forcing users to switch platforms unnecessarily.

Examples:

Proton Drive: File sharing cannot be initiated from the mobile or desktop app and requires opening the web version. Sharing should be possible directly within the apps.

Calendar: Sharing a calendar with another Proton user currently works only on desktop, not on mobile.
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