Summary: Syften adds tiered archive search limits

Why It Matters: The product now limits how far back users can search for old mentions based on their pay tier. This creates a clear reason for users to upgrade to more expensive plans.

What Changed:

• Added "Archive search: 7 days" to the Entry plan.
• Added "Archive search: 1 month" to the Standard plan.
• Added "Archive search: unlimited" to the Syften PRO plan.
• Updated plan descriptions to highlight "more archive" and "unlimited archive" features.