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-network-packet-capture-analysis/SKILL.md

@@ -1,8 +1,9 @@
 ---
 name: performing-network-packet-capture-analysis
-description: Perform forensic analysis of network packet captures (PCAP/PCAPNG) using Wireshark, tshark, and tcpdump to reconstruct
-  network communications, extract transferred files, identify malicious traffic, and establish evidence of data exfiltration
-  or command-and-control activity.
+description: Perform forensic analysis of network packet captures (PCAP/PCAPNG) using
+  Wireshark, tshark, and tcpdump to reconstruct network communications, extract transferred
+  files, identify malicious traffic, and establish evidence of data exfiltration or
+  command-and-control activity.
 domain: cybersecurity
 subdomain: digital-forensics
 tags:
@@ -24,6 +25,12 @@ nist_csf:
 - RS.AN-03
 - DE.AE-02
 - RS.MA-01
+mitre_attack:
+- T1005
+- T1074
+- T1119
+- T1070
+- T1048
 ---
 
 # Performing Network Packet Capture Analysis