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/collecting-open-source-intelligence/SKILL.md

@@ -1,10 +1,12 @@
 ---
 name: collecting-open-source-intelligence
-description: 'Collects and synthesizes open-source intelligence (OSINT) about threat actors, malicious infrastructure, and
-  attack campaigns using publicly available data sources, passive reconnaissance tools, and dark web monitoring. Use when
-  investigating external threat actor infrastructure, performing pre-engagement reconnaissance for authorized red team assessments,
-  or enriching CTI reports with publicly available adversary context. Activates for requests involving Maltego, Shodan, OSINT
-  framework, SpiderFoot, or infrastructure reconnaissance.
+description: 'Collects and synthesizes open-source intelligence (OSINT) about threat
+  actors, malicious infrastructure, and attack campaigns using publicly available
+  data sources, passive reconnaissance tools, and dark web monitoring. Use when investigating
+  external threat actor infrastructure, performing pre-engagement reconnaissance for
+  authorized red team assessments, or enriching CTI reports with publicly available
+  adversary context. Activates for requests involving Maltego, Shodan, OSINT framework,
+  SpiderFoot, or infrastructure reconnaissance.
 
   '
 domain: cybersecurity
@@ -26,6 +28,12 @@ nist_csf:
 - ID.RA-05
 - DE.CM-01
 - DE.AE-02
+mitre_attack:
+- T1593.001
+- T1589.002
+- T1596.002
+- T1590
+- T1596.001
 ---
 # Collecting Open-Source Intelligence