Memorystore for Redis Instance Discovery

The extension discovers Memorystore for Redis instances across accessible projects and regions. Each instance is exposed as a target with attributes for its tier (BASIC / STANDARD_HA), Redis version, memory size, current / alternative zone, replica count, read-replica mode, and endpoint host.

The tier attribute lets you scope failover attacks to STANDARD_HA instances only, since failover is not supported on BASIC tier.