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/eradicating-malware-from-infected-systems/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: eradicating-malware-from-infected-systems
-description: Systematically remove malware, backdoors, and attacker persistence mechanisms from infected systems while ensuring
-  complete eradication and preventing re-infection.
+description: Systematically remove malware, backdoors, and attacker persistence mechanisms
+  from infected systems while ensuring complete eradication and preventing re-infection.
 domain: cybersecurity
 subdomain: incident-response
 tags:
@@ -11,10 +11,11 @@ tags:
 - persistence
 - dfir
 mitre_attack:
+- T1486
+- T1490
+- T1070
+- T1078
 - T1547
-- T1053
-- T1543
-- T1574
 version: '1.0'
 author: mahipal
 license: Apache-2.0