Infrastructure composability audit: Exa client, Tier-2 fixes, core/project layering #256

Job	Run time
Detect optional projects	7s
Lint & Type Check	34s
Security Scan	28s
Unified Health Report (informational)	46s
Documentation Lint	3m 37s
Validate Manuscripts	21s
Verify No Mocks Policy	13s
Infra Tests (ubuntu-latest, Python 3.12)	15m 56s
Project Tests (ubuntu-latest, Python 3.10)	30m 15s
Infra Tests (ubuntu-latest, Python 3.11)	15m 51s
Infra Tests (macos-latest, Python 3.12)	16m 50s
Project Tests (macos-latest, Python 3.12)	30m 19s
Infra Tests (macos-latest, Python 3.10)	17m 16s
Infra Tests (macos-latest, Python 3.11)	16m 52s
Project Tests (ubuntu-latest, Python 3.12)	30m 16s
Project Tests (macos-latest, Python 3.10)	30m 52s
Project Tests (ubuntu-latest, Python 3.11)	30m 15s
Infra Tests (ubuntu-latest, Python 3.10)	14m 8s
Project Tests (macos-latest, Python 3.11)	30m 18s
fep_lean (gauss + lake)	0s
Setup hook (Windows smoke)	0s
Performance Check	-1s
	4h 45m 13s

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