feat(messaging): Add comprehensive messaging system with conversations and UI #175

Job	Run time
Security & Code Quality	1m 16s
Test Suite	1m 2s
Build & Performance	3m 53s
Database Tests	1m 0s
Enhanced Security Testing	4m 51s
Deploy to Production	0s
Rollback on Failure	0s
Deploy to Staging	0s
Performance Monitoring	0s
Performance Monitoring (Staging)	-1s
	12m 1s

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