Rewrite 548 skill descriptions to the activation rubric

Each rewritten description now states both what the skill does (concrete
capability, named tools/artifacts) and an explicit when-to-use trigger,
improving agent discovery/activation. Grounded in each skill's own body;
changes confined to the `description` field only (bodies and all other
frontmatter untouched). Produced by a gated audit->rewrite->recheck loop
(548 -> 0 flagged) with a sampled anti-invention check (0 ungrounded).

Schema: 817/817 pass. Framework-ID gate: 0 defects.

skills/scanning-network-with-nmap-advanced/SKILL.md

@@ -1,9 +1,11 @@
 ---
 name: scanning-network-with-nmap-advanced
-description: 'Performs advanced network reconnaissance using Nmap''s scripting engine,
-  timing controls, evasion techniques, and output parsing to discover hosts, enumerate
-  services, detect vulnerabilities, and fingerprint operating systems across authorized
-  target networks.
+description: 'Performs advanced network recon using Nmap''s Scripting Engine (NSE),
+  timing controls, firewall/IDS evasion, and structured output parsing to discover
+  hosts, enumerate service versions, detect vulnerabilities, and fingerprint OSes.
+  Use during authorized penetration tests or enterprise asset-discovery assessments
+  needing scan evasion, NSE vulnerability checks, or output fed into a vulnerability
+  management pipeline.
 
   '
 domain: cybersecurity