SEC-ORCH-28: Add connectTimeout (5000ms default) and commandTimeout
(3000ms default) to Valkey/Redis client to prevent indefinite connection
hangs. Both are configurable via VALKEY_CONNECT_TIMEOUT_MS and
VALKEY_COMMAND_TIMEOUT_MS environment variables.
SEC-ORCH-29: Add @ArrayMaxSize(50) and @MaxLength(2000) to workItems
in AgentContextDto to prevent memory exhaustion from unbounded input.
Also adds @ArrayMaxSize(20) and @MaxLength(200) to skills array.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>