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/detecting-privilege-escalation-attempts/SKILL.md

@@ -1,8 +1,6 @@
 ---
 name: detecting-privilege-escalation-attempts
-description: Detect privilege escalation attempts including token manipulation, UAC
-  bypass, unquoted service paths, kernel exploits, and sudo/doas abuse across Windows
-  and Linux.
+description: Detect privilege escalation attempts across Windows and Linux, including access token manipulation, UAC bypass, unquoted service path abuse, kernel exploits, and sudo/doas abuse. Use when threat hunting for T1068-style privilege escalation, triaging EDR/SIEM alerts on suspicious privilege changes, scoping compromise during incident response, or validating detection coverage in a purple team exercise.
 domain: cybersecurity
 subdomain: threat-hunting
 tags: