KIP-737 — Add canTrackSource to ReplicationPolicy

Discussion Kafka 3.0 MirrorMaker

KIP-737 adds a `canTrackSource()` method to the `ReplicationPolicy` interface in MirrorMaker 2, allowing implementations to declare whether they can reverse-map a topic name back to its source cluster. Without this capability, the `IdentityReplicationPolicy` (needed for MirrorMaker 1 migration) cannot coexist cleanly with MM2's offset syncing logic, which assumes topic names encode source cluster identity.

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