feat: Implement comprehensive Market Manager with database and logging

- Add complete Market Manager package with in-memory storage and CRUD operations
- Implement arbitrage detection with profit calculations and thresholds
- Add database adapter with PostgreSQL schema for persistence
- Create comprehensive logging system with specialized log files
- Add detailed documentation and implementation plans
- Include example application and comprehensive test suite
- Update Makefile with market manager build targets
- Add check-implementations command for verification

go.sum

@@ -114,6 +114,8 @@ github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0
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+github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
+github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
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