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-ransomware-tabletop-exercise/SKILL.md

@@ -1,10 +1,12 @@
 ---
 name: performing-ransomware-tabletop-exercise
-description: 'Plans and facilitates tabletop exercises simulating ransomware incidents to test organizational readiness, decision-making,
-  and communication procedures. Designs realistic scenarios based on current ransomware threat actors (LockBit, ALPHV/BlackCat,
-  Cl0p), injects covering double extortion, backup destruction, and regulatory notification requirements. Evaluates participant
-  responses against NIST CSF and CISA guidelines. Activates for requests involving ransomware tabletop, incident response
-  exercise, or ransomware readiness drill.
+description: 'Plans and facilitates tabletop exercises simulating ransomware incidents
+  to test organizational readiness, decision-making, and communication procedures.
+  Designs realistic scenarios based on current ransomware threat actors (LockBit,
+  ALPHV/BlackCat, Cl0p), injects covering double extortion, backup destruction, and
+  regulatory notification requirements. Evaluates participant responses against NIST
+  CSF and CISA guidelines. Activates for requests involving ransomware tabletop, incident
+  response exercise, or ransomware readiness drill.
 
   '
 domain: cybersecurity
@@ -23,6 +25,12 @@ nist_csf:
 - RS.MA-01
 - RC.RP-01
 - PR.IR-01
+mitre_attack:
+- T1078
+- T1190
+- T1059
+- T1486
+- T1490
 ---
 # Performing Ransomware Tabletop Exercise