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/mapping-mitre-attack-techniques/SKILL.md

@@ -1,9 +1,11 @@
 ---
 name: mapping-mitre-attack-techniques
-description: 'Maps observed adversary behaviors, security alerts, and detection rules to MITRE ATT&CK techniques and sub-techniques
-  to quantify detection coverage and guide control prioritization. Use when building an ATT&CK-based coverage heatmap, tagging
-  SIEM alerts with technique IDs, aligning security controls to adversary playbooks, or reporting threat exposure to executives.
-  Activates for requests involving ATT&CK Navigator, Sigma rules, MITRE D3FEND, or coverage gap analysis.
+description: 'Maps observed adversary behaviors, security alerts, and detection rules
+  to MITRE ATT&CK techniques and sub-techniques to quantify detection coverage and
+  guide control prioritization. Use when building an ATT&CK-based coverage heatmap,
+  tagging SIEM alerts with technique IDs, aligning security controls to adversary
+  playbooks, or reporting threat exposure to executives. Activates for requests involving
+  ATT&CK Navigator, Sigma rules, MITRE D3FEND, or coverage gap analysis.
 
   '
 domain: cybersecurity
@@ -38,6 +40,12 @@ nist_csf:
 - ID.RA-05
 - DE.CM-01
 - DE.AE-02
+mitre_attack:
+- T1591
+- T1592
+- T1593
+- T1589
+- T1685.002
 ---
 # Mapping MITRE ATT&CK Techniques