Add index on clinic_activity_logs.numeric_value to fix performance issue-created-by-agentic

[shaykeren]

This PR addresses a critical performance incident (ID: 5aa1fb7a-3656-11f0-8db3-ca59c7e8e81d) affecting the clinic activity logs query endpoint.

Problem

• Query performance degradation in clinic_activity_logs table
• Execution time increased from 592.55 microseconds to 4.7 seconds
• Sequential scan being performed due to missing index
• Cache hit rate dropped to 3.9%

Solution

• Added B-tree index on numeric_value column
• Added SQL migration file with proper documentation
• Verified performance improvement after index creation

Performance Impact

Before:

• Execution time: 4.7 seconds
• Sequential scan on full table

After:

• Execution time: 0.338 ms
• Uses index scan
• Performance improvement: ~13,900x faster

Testing

• Verified query execution plan shows index usage
• Confirmed significant performance improvement
• No negative impact on other operations

Related

• Issue ID: 5aa1fb7a-3656-11f0-8db3-ca59c7e8e81d
• Bottleneck ID: 14dbd63a-4554-11f0-b280-42975a299f33
• Trace ID: 991EE270CADB746CFF97AB98303DF3C2