AgentCore 0.18.0

Fixed

• Compaction now counts reasoning_content in loop and middleware token estimates and drops it from older assistant turns (Tier 1 keeps at least the latest turn, or the last keep_tool_result turns when greater than one; tool-result compression and the Tier 2 input keep only the latest). Long thinking_format: reasoning_content runs previously looked ~19x smaller than their real prompts, so compaction rarely fired; expect compaction to trigger earlier and prompts to shrink on those profiles. Proxy compatibility was verified with llm-hub deepseek-flash; the self-hosted DSV4 checkpoint and long-task quality were not tested.