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/building-attack-pattern-library-from-cti-reports/SKILL.md

@@ -1,7 +1,8 @@
 ---
 name: building-attack-pattern-library-from-cti-reports
-description: Extract and catalog attack patterns from cyber threat intelligence reports into a structured STIX-based library
-  mapped to MITRE ATT&CK for detection engineering and threat-informed defense.
+description: Extract and catalog attack patterns from cyber threat intelligence reports
+  into a structured STIX-based library mapped to MITRE ATT&CK for detection engineering
+  and threat-informed defense.
 domain: cybersecurity
 subdomain: threat-intelligence
 tags:
@@ -27,6 +28,12 @@ nist_csf:
 - ID.RA-05
 - DE.CM-01
 - DE.AE-02
+mitre_attack:
+- T1566.001
+- T1059.001
+- T1003.001
+- T1558.003
+- T1550.002
 ---
 # Building Attack Pattern Library from CTI Reports