Map all 754 skills to MITRE ATT&CK v19.1

- Add validated mitre_attack frontmatter to all 754 skills (286 distinct
  techniques), verified against MITRE ATT&CK v19.1 via the official
  mitreattack-python library: 0 revoked, deprecated, or invalid IDs
- Curate precise per-skill technique IDs for forensics, malware-analysis,
  threat-intel, and red-team skills (e.g. DCSync -> T1003.006,
  Kerberoasting -> T1558.003, Pass-the-Ticket -> T1550.003)
- Reconcile v19.1 tactic restructuring: Defense Evasion split into
  Stealth (TA0005) and Defense Impairment (TA0112); revoked T1562.*
  family and T1070.001/.002 remapped to active equivalents (T1685.*)
- Normalize word-split tags across 35 skills (remove filename-derived
  stopword tags, add semantic cybersecurity tags)
- Add api-reference.md for 3 skills that were missing it
- Update README ATT&CK section with accurate v19.1 tactic distribution

skills/performing-graphql-introspection-attack/SKILL.md

@@ -1,9 +1,11 @@
 ---
 name: performing-graphql-introspection-attack
-description: 'Performs GraphQL introspection attacks to extract the full API schema including types, queries, mutations, subscriptions,
-  and field definitions from GraphQL endpoints. The tester uses introspection queries to map the attack surface, identifies
-  sensitive fields and mutations, tests for query depth and complexity limits, and exploits GraphQL-specific vulnerabilities
-  including batching attacks, alias-based brute force, and nested query DoS. Activates for requests involving GraphQL security
+description: 'Performs GraphQL introspection attacks to extract the full API schema
+  including types, queries, mutations, subscriptions, and field definitions from GraphQL
+  endpoints. The tester uses introspection queries to map the attack surface, identifies
+  sensitive fields and mutations, tests for query depth and complexity limits, and
+  exploits GraphQL-specific vulnerabilities including batching attacks, alias-based
+  brute force, and nested query DoS. Activates for requests involving GraphQL security
   testing, introspection attack, GraphQL enumeration, or GraphQL API penetration testing.
 
   '
@@ -23,6 +25,11 @@ nist_csf:
 - ID.RA-01
 - PR.DS-10
 - DE.CM-01
+mitre_attack:
+- T1190
+- T1059.007
+- T1552.001
+- T1110
 ---
 # Performing GraphQL Introspection Attack