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/analyzing-powershell-script-block-logging/SKILL.md

@@ -1,8 +1,10 @@
 ---
 name: analyzing-powershell-script-block-logging
-description: Parse Windows PowerShell Script Block Logs (Event ID 4104) from EVTX files to detect obfuscated commands, encoded
-  payloads, and living-off-the-land techniques. Uses python-evtx to extract and reconstruct multi-block scripts, applies entropy
-  analysis and pattern matching for Base64-encoded commands, Invoke-Expression abuse, download cradles, and AMSI bypass attempts.
+description: Parse Windows PowerShell Script Block Logs (Event ID 4104) from EVTX
+  files to detect obfuscated commands, encoded payloads, and living-off-the-land techniques.
+  Uses python-evtx to extract and reconstruct multi-block scripts, applies entropy
+  analysis and pattern matching for Base64-encoded commands, Invoke-Expression abuse,
+  download cradles, and AMSI bypass attempts.
 domain: cybersecurity
 subdomain: security-operations
 tags:
@@ -20,6 +22,11 @@ nist_csf:
 - RS.MA-01
 - GV.OV-01
 - DE.AE-02
+mitre_attack:
+- T1059.001
+- T1027.010
+- T1140
+- T1105
 ---