docs(skills): rewrite container-security descriptions to a uniform standard

All 33 container-security skills now carry what it does, an explicit
"Use when" trigger, keywords, and a negative trigger naming the nearest
neighbour. Six collision clusters resolved by differentiating scope
rather than merging, so no skill is removed:

- kube-bench: running the tool vs interpreting findings into an audit
- Calico: portable upstream NetworkPolicy vs Calico-as-CNI vs Calico-only
  CRDs (GlobalNetworkPolicy, HostEndpoint, DNS egress)
- Falco: deploying and operating it vs authoring escape rules
- container escape: tool-agnostic runtime signals vs Falco rule syntax vs
  static posture audit vs offensive breakout
- Trivy: all-target platform and operator vs single-image scan
- Docker: images and Dockerfiles vs daemon.json vs the CIS audit script

Also replaces the templated "When to Use" boilerplate in these files,
including bullets that only restated the skill's own name.

Worst pair (Pod Security Standards vs Pod Security Admission) drops from
0.77 cosine to below the 0.45 threshold. Repo-wide: colliding pairs
60 -> 56, skills involved 105 -> 94.

skills/implementing-kubernetes-network-policy-with-calico/SKILL.md

@@ -1,12 +1,15 @@
 ---
 name: implementing-kubernetes-network-policy-with-calico
 description: >-
-  Implements Kubernetes network segmentation using Calico's Kubernetes
-  NetworkPolicy and GlobalNetworkPolicy resources, including default-deny rules,
-  policy ordering, and service-account-based selectors for zero-trust
-  pod-to-pod communication. Use when installing Calico CNI and writing or
-  auditing network policies to restrict east-west traffic within a Kubernetes
-  cluster.
+  Installs Calico as the cluster CNI and writes standard Kubernetes NetworkPolicy under it,
+  covering default-deny baselines, policy ordering and precedence, service-account-based
+  selectors, and verifying that policy is genuinely being enforced. Use when adopting Calico
+  as the enforcement CNI, establishing a default-deny baseline, or debugging why a
+  NetworkPolicy is not taking effect under Calico. Keywords: Calico CNI, NetworkPolicy,
+  default deny, policy order, Felix, service account selector. Do not use for Calico-only CRDs
+  such as GlobalNetworkPolicy or DNS egress - use
+  implementing-container-network-policies-with-calico; for CNI-agnostic policy use
+  implementing-network-policies-for-kubernetes.
 domain: cybersecurity
 subdomain: container-security
 tags: