feat(split-brain): Introduce lease mechanism for Kvrocks master

[redwood9]

As discussed in the KvRocks split-brain issue (apache/kvrocks#3380)
here is the first step of the proposed solution: Introduce a lease mechanism to KvRocks.
This involves the following changes:

KvRocks side:
Add lease support inside KvRocks
Implement periodic lease refresh (heartbeat) when the feature is enabled
apache/kvrocks#3397

Controller side:
When performing master detection/probing, also fetch and synchronize:
Current master information
Lease-related information (especially lease expiration/TTL)

Add new configuration for lease duration / refresh interval

Lease heartbeat is strictly opt-in via configuration:

If the lease-related config is not set (or explicitly disabled), KvRocks and the controller behave exactly the same as today — no extra overhead, no behavioral change.
Only when the lease feature is explicitly enabled in the config will KvRocks start sending lease refresh heartbeats and the controller will begin comparing master info + lease validity during failover checks.