feat: allow hide private subscription in view timeline

[hyoban]

Description

PR Type

• Feature
• Bugfix
• Hotfix
• Other (please describe):

Screenshots (if UI change)

Demo Video (if new feature)

Linked Issues

• close Hide private subscription feeds #773
• https://github.com/RSSNext/follow-server/pull/318

Additional context

Changelog

• I have updated the changelog/next.md with my changes.

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Name	Status	Preview	Comments	Updated (UTC)
follow	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	May 22, 2025 8:59am

1 Skipped Deployment

Name	Status	Preview	Comments	Updated (UTC)
follow-external-ssr	⬜️ Ignored (Inspect)	Visit Preview		May 22, 2025 8:59am

[follow-reviewer-bot]

Suggested PR Title:

feat(settings): add option to hide private subs in timeline

Change Summary:
Added a new general setting 'hidePrivateSubscriptionsInTimeline' for both desktop and mobile apps, allowing users to hide private subscriptions from the timeline view. Updated relevant hooks, queries, and store logic to respect this setting when fetching and marking entries. Extended settings UI, default settings, and translations to support the new option. This enhances user control over timeline content visibility.

Code Review:
No change requests necessary.