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/implementing-syslog-centralization-with-rsyslog/SKILL.md

@@ -1,15 +1,18 @@
 ---
 name: implementing-syslog-centralization-with-rsyslog
-description: Configure rsyslog for centralized log collection with TLS encryption, custom templates, and log rotation. Generates
-  server and client configuration files with GnuTLS stream drivers, x509 certificate authentication, per-host log segregation,
+description: Configure rsyslog for centralized log collection with TLS encryption,
+  custom templates, and log rotation. Generates server and client configuration files
+  with GnuTLS stream drivers, x509 certificate authentication, per-host log segregation,
   and reliable queue settings for high-availability syslog infrastructure.
 domain: cybersecurity
 subdomain: security-operations
 tags:
-- implementing
 - syslog
-- centralization
-- with
+- rsyslog
+- log-centralization
+- tls-encryption
+- log-management
+- security-operations
 version: '1.0'
 author: mahipal
 license: Apache-2.0
@@ -18,6 +21,12 @@ nist_csf:
 - RS.MA-01
 - GV.OV-01
 - DE.AE-02
+mitre_attack:
+- T1078
+- T1190
+- T1059
+- T1573
+- T1486
 ---