Add LogZero to Applications

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Adds LogZero to the Applications section.

LogZero is a private, on-device life and habit tracker for iOS (iPhone & iPad) whose modules include mood and meditation tracking, with a local correlation engine and dashboard for spotting patterns in emotional well-being. It works fully offline: no account, no ads, no analytics or telemetry, and zero network requests for user data (App Store privacy label "Data Not Collected").

• Website: https://logzero.app
• App Store: https://apps.apple.com/app/id6773557137

Guideline checklist:

• Individual pull request for a single suggestion.
• Title-cased name; added in alphabetical order (between Headspace and MindShift CBT).
• Format matches neighboring Applications entries: * [Name](link) – Short description.
• Small-app entry (exempt from the clinical-evidence requirement per the contributing guidelines).
• No trailing whitespace; spelling and grammar checked.