docs: update minimum cores for Boost to 5,000 (#491)

Updated the minimum daily budget for boosting posts and Squads from
1,000 cores to 5,000 cores in the Boost documentation.

Co-authored-by: Claude <noreply@anthropic.com>

Author: nimrodkra

docs/monetization/boost.md

@@ -57,8 +57,8 @@ Promote your entire Squad to attract new members and grow your community.
 
 ## Budget and duration
 
-- **Daily budget**:  
-  - Minimum: 1,000 cores  
+- **Daily budget**:
+  - Minimum: 5,000 cores
   - Maximum: 100,000 cores  
 - **Duration**: 1–30 days  
 - **Total spend**: `daily budget × number of days`