#253 Add gc pause time to ai prompt

[kkazmierczyk]

Fixes #253

Summary

• add GC pause time data to the AI performance recommendations prompt
• include detailed per-collection pause entries for smaller GC datasets
• include summarized pause statistics for larger GC datasets
• add reference guidance that typical GC pause targets are in the 500-2000 ms range

Details

• PerformanceRecommendationsPrompter now computes GC pause context and injects it into the prompt
• for fewer than 100 GC collections, the prompt receives timestamped pause durations
• for 100 or more GC collections, the prompt receives summary metrics including total count, average, min, max, and counts over 1000 ms and 2000 ms
• the prompt template was updated to include a dedicated GC Pause Times section
• a new constant is used to control the threshold between detailed and summarized output

[kkazmierczyk]

Added 2 new lines