fix: Add missing created_at field in SessionSummary tests #8

Job	Run time
Clippy	1m 7s
Security Audit	1m 0s
Test (ubuntu-latest)	8m 41s
Test (macos-latest)	7m 52s
Format	14s
Build Check (macos-latest)	1m 13s
Build Check (ubuntu-latest)	1m 2s
Build Check (blacksmith-4vcpu-windows-2025)	1m 4s
Test (blacksmith-4vcpu-windows-2025)	2m 52s
	25m 5s

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