Starter Kits: Add support for list of IDs

[obenland]

Fixes #2037.

Proposed changes:

• Updated the import logic to consistently treat items as actor IDs, ensuring they are strings and valid URLs before attempting to follow.

Demo files:

starter-kit.json (actor objects)
starter-kit-2.json (list of actor ids and webfingers)

Changelog entry

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Changelog Entry Details

Significance

• Patch
• Minor
• Major

Type

• Added - for new features
• Changed - for changes in existing functionality
• Deprecated - for soon-to-be removed features
• Removed - for now removed features
• Fixed - for any bug fixes
• Security - in case of vulnerabilities

Message

Added support for list of Actor IDs in Starter Kits.

[Copilot]

Pull Request Overview

This PR updates the starter kit import logic to support a list of actor IDs by treating all items consistently as actor IDs. The change improves the handling of different input formats (strings vs objects) and adds URL validation before attempting to follow actors.

• Updated variable naming from $item to $actor_id for clarity
• Added string conversion and URL validation for actor IDs
• Simplified the follow operation by using the actor ID directly