Remove backed-up duplicate skills to fix validation pipeline

skills/implementing-zero-knowledge-proof-for-authentication/SKILL.md

@@ -14,6 +14,21 @@ license: Apache-2.0
 
 Zero-Knowledge Proofs (ZKPs) allow a prover to demonstrate knowledge of a secret (such as a password or private key) without revealing the secret itself. This skill implements the Schnorr identification protocol and a simplified ZKPP (Zero-Knowledge Password Proof) using the discrete logarithm problem, enabling authentication where the server never learns the user's password.
 
+
+## When to Use
+
+- When deploying or configuring implementing zero knowledge proof for authentication 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
 
 - Implement Schnorr's identification protocol for ZKP authentication