inconsistent interface with snake_case and camelCase parameters on some clients.

[Hweinstock]

Problem

Some methods exposed accept parameters with snake_case and some accept them via camelCase. This is a result of leveraging direct botocore passthroughs in addition to high-level constructs.

The result is an inconsistent interface for customers that can cause confusion:
Ex.

from bedrock_agentcore.memory import MemoryClient

client = MemoryClient(region_name="us-west-2")

# Explicit SDK method — snake_case
memory = client.create_memory(
    name="my-memory",
    memory_execution_role_arn="arn:aws:iam::123456789012:role/MyRole",
    event_expiry_days=90,
)

#   Passthrough method — forced to use camelCase (boto3 convention)
client.update_memory(
    memoryId=memory["id"],
    clientToken="tok-123",
    streamDeliveryResources={...},
)

Acceptance Criteria

• user is able to consistently pass in snake_case or camelCase to all methods.
• avoids breaking existing experience, unless a major version bump is done.