Redisson Migration and Distributed Locks

Migrated from Spring Data Redis to Redisson for a richer Redis client experience.

Redisson Migration

- spring-data-redis RedisTemplate
+ Redisson: RMap, RSet, RLock, etc.

Redisson provides richer distributed data structures, built-in distributed locks, more efficient serialization, and connection pooling.

Lock Abstraction

// Local lock (single JVM)
lockService.acquireLocal("order-process", () -> {
    // critical section
});

// Distributed lock (multi-instance)
lockService.acquireDistributed("order-process", () -> {
    // critical section across all instances
});

+ LockService interface
+ LocalLockService: ReentrantLock-based
+ DistributedLockService: Redisson-based
+ Configurable lock timeout and retry