Remove backed-up duplicate skills to fix validation pipeline

skills/detecting-oauth-token-theft/SKILL.md

@@ -16,3 +16,18 @@ license: Apache-2.0
 
 Analyze OAuth sign-in telemetry for indicators of token theft including
 impossible travel, device fingerprint changes, and token replay attacks.
+
+
+## When to Use
+
+- When investigating security incidents that require detecting oauth token theft
+- When building detection rules or threat hunting queries for this domain
+- When SOC analysts need structured procedures for this analysis type
+- When validating security monitoring coverage for related attack techniques
+
+## Prerequisites
+
+- Familiarity with identity security 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