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-containers-with-trivy-in-cicd/SKILL.md

@@ -1,10 +1,11 @@
 ---
 name: scanning-containers-with-trivy-in-cicd
-description: 'This skill covers integrating Aqua Security''s Trivy scanner into CI/CD
-  pipelines for comprehensive container image vulnerability detection. It addresses
-  scanning Docker images for OS package and application dependency CVEs, detecting
-  misconfigurations in Dockerfiles, scanning filesystem and git repositories, and
-  establishing severity-based quality gates that block deployment of vulnerable images.
+description: 'Integrates Aqua Security''s Trivy scanner into CI/CD pipelines to detect
+  OS package and application dependency CVEs, Dockerfile misconfigurations, and issues
+  in filesystems or git repositories, and to enforce severity-based quality gates that
+  block vulnerable images from being deployed. Use when building Docker images in
+  CI/CD and needing automated vulnerability scanning and pass/fail gates before registry
+  push or production deployment.
 
   '
 domain: cybersecurity