feat: grpc 기능 deep 구현

src/grpc/grpc-operation-ledger-jpa/build.gradle

@@ -0,0 +1,17 @@
+apply plugin: 'java-library'
+
+// Durable mutation idempotency: the operation ledger entity, its state machine, the vendor-neutral
+// repository port and the Spring Data JPA binding, plus the migration that owns the unique
+// constraint the whole contract rests on.
+//
+// The port is what the policy layer consumes; the Spring Data interface is the adapter. Tests here
+// run against a hand-rolled in-memory port implementation — a real datastore is only justified when
+// vendor semantics are the thing under test, and the constraint is asserted by the migration.
+dependencies {
+    api project(':grpc:grpc-core-api')
+
+    // api: the ledger entity is a public JPA type and the repository interface is a public Spring
+    // Data type, so both vendor APIs appear in this module's public signatures.
+    api 'jakarta.persistence:jakarta.persistence-api'
+    api 'org.springframework.data:spring-data-jpa'
+}