Remove backed-up duplicate skills to fix validation pipeline

skills/implementing-envelope-encryption-with-aws-kms/SKILL.md

@@ -14,6 +14,21 @@ license: Apache-2.0
 
 Envelope encryption is a strategy where data is encrypted with a data encryption key (DEK), and the DEK itself is encrypted with a master key (KEK) managed by AWS KMS. This approach allows encrypting large volumes of data locally while keeping the master key secure in a hardware security module (HSM) managed by AWS. This skill covers implementing envelope encryption using AWS KMS GenerateDataKey API.
 
+
+## When to Use
+
+- When deploying or configuring implementing envelope encryption with aws kms capabilities in your environment
+- When establishing security controls aligned to compliance requirements
+- When building or improving security architecture for this domain
+- When conducting security assessments that require this implementation
+
+## Prerequisites
+
+- Familiarity with cryptography concepts and tools
+- Access to a test or lab environment for safe execution
+- Python 3.8+ with required dependencies installed
+- Appropriate authorization for any testing activities
+
 ## Objectives
 
 - Understand the envelope encryption pattern and its advantages