feat(admin): add index management operations

Add createIndex and dropIndex methods to AdminClient with corresponding
validation logic. These methods enable management of database indexes on
boundaries, including proper request validation, error handling, and
logging.

Updated documentation to include usage examples for the new index
management functionality.

Author: oexza

CLAUDE.md

@@ -99,6 +99,7 @@ The `AdminClient` class mirrors the architecture of `OrisunClient` but focuses o
 - **User Management**: `createUser`, `deleteUser`, `changePassword`, `listUsers`
 - **Authentication**: `validateCredentials`
 - **Statistics**: `getUserCount`, `getEventCount`
+- **Index Management**: `createIndex`, `dropIndex`
 
 Both clients share the same authentication flow, token caching mechanism, and connection management patterns.
 
@@ -232,4 +233,36 @@ if (response.getSuccess()) {
 ```java
 long userCount = adminClient.getUserCount();
 long eventCount = adminClient.getEventCount("users-boundary");
+```
+
+**Creating an index:**
+```java
+CreateIndexRequest request = CreateIndexRequest.newBuilder()
+    .setBoundary("events-boundary")
+    .setName("idx_user_id")
+    .addFields(IndexField.newBuilder()
+        .setJsonKey("userId")
+        .setValueType(ValueType.TEXT)
+        .build())
+    .addFields(IndexField.newBuilder()
+        .setJsonKey("timestamp")
+        .setValueType(ValueType.TIMESTAMPTZ)
+        .build())
+    .addConditions(IndexCondition.newBuilder()
+        .setKey("eventType")
+        .setOperator("=")
+        .setValue("UserCreated")
+        .build())
+    .setConditionCombinator(ConditionCombinator.AND)
+    .build();
+adminClient.createIndex(request);
+```
+
+**Dropping an index:**
+```java
+DropIndexRequest request = DropIndexRequest.newBuilder()
+    .setBoundary("events-boundary")
+    .setName("idx_user_id")
+    .build();
+adminClient.dropIndex(request);
 ```

protos

@@ -472,6 +472,48 @@ public long getEventCount(String boundary) throws OrisunException {
         return getEventCount(GetEventCountRequest.newBuilder().setBoundary(boundary).build());
     }
 
+    // Index Management Operations
+
+    /**
+     * Create a new index on a boundary
+     */
+    public void createIndex(CreateIndexRequest request) throws OrisunException {
+        AdminRequestValidator.validateCreateIndexRequest(request);
+
+        logger.debug("Creating index '{}' on boundary: {}", request.getName(), request.getBoundary());
+
+        try {
+            blockingStub
+                    .withDeadlineAfter(defaultTimeoutSeconds, TimeUnit.SECONDS)
+                    .createIndex(request);
+
+            logger.info("Successfully created index '{}' on boundary: {}", request.getName(), request.getBoundary());
+
+        } catch (StatusRuntimeException e) {
+            throw handleException(e, "createIndex");
+        }
+    }
+
+    /**
+     * Drop an index from a boundary
+     */
+    public void dropIndex(DropIndexRequest request) throws OrisunException {
+        AdminRequestValidator.validateDropIndexRequest(request);
+
+        logger.debug("Dropping index '{}' from boundary: {}", request.getName(), request.getBoundary());
+
+        try {
+            blockingStub
+                    .withDeadlineAfter(defaultTimeoutSeconds, TimeUnit.SECONDS)
+                    .dropIndex(request);
+
+            logger.info("Successfully dropped index '{}' from boundary: {}", request.getName(), request.getBoundary());
+
+        } catch (StatusRuntimeException e) {
+            throw handleException(e, "dropIndex");
+        }
+    }
+
     private OrisunException handleException(StatusRuntimeException e, String operation) {
         Map<String, Object> context = new HashMap<>();
         context.put("operation", operation);

src/main/java/com/orisunlabs/orisun/client/AdminClient.java

@@ -172,4 +172,53 @@ public static void validateGetEventCountRequest(GetEventCountRequest request) {
                     .addContext("operation", "getEventCount");
         }
     }
+
+    /**
+     * Validate a CreateIndexRequest
+     */
+    public static void validateCreateIndexRequest(CreateIndexRequest request) {
+        if (request == null) {
+            throw new OrisunException("CreateIndexRequest cannot be null")
+                    .addContext("operation", "createIndex");
+        }
+
+        if (request.getBoundary() == null || request.getBoundary().trim().isEmpty()) {
+            throw new OrisunException("Boundary is required")
+                    .addContext("operation", "createIndex");
+        }
+
+        if (request.getName() == null || request.getName().trim().isEmpty()) {
+            throw new OrisunException("Index name is required")
+                    .addContext("operation", "createIndex")
+                    .addContext("boundary", request.getBoundary());
+        }
+
+        if (request.getFieldsCount() == 0) {
+            throw new OrisunException("At least one field is required")
+                    .addContext("operation", "createIndex")
+                    .addContext("boundary", request.getBoundary())
+                    .addContext("indexName", request.getName());
+        }
+    }
+
+    /**
+     * Validate a DropIndexRequest
+     */
+    public static void validateDropIndexRequest(DropIndexRequest request) {
+        if (request == null) {
+            throw new OrisunException("DropIndexRequest cannot be null")
+                    .addContext("operation", "dropIndex");
+        }
+
+        if (request.getBoundary() == null || request.getBoundary().trim().isEmpty()) {
+            throw new OrisunException("Boundary is required")
+                    .addContext("operation", "dropIndex");
+        }
+
+        if (request.getName() == null || request.getName().trim().isEmpty()) {
+            throw new OrisunException("Index name is required")
+                    .addContext("operation", "dropIndex")
+                    .addContext("boundary", request.getBoundary());
+        }
+    }
 }