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/implementing-data-loss-prevention-with-microsoft-purview/SKILL.md

@@ -1,15 +1,11 @@
 ---
 name: implementing-data-loss-prevention-with-microsoft-purview
-description: 'Implements data loss prevention policies using Microsoft Purview to
-  protect sensitive information across Exchange Online, SharePoint, OneDrive, Teams,
-  endpoint devices, and Power BI. The analyst configures sensitivity labels with encryption
-  and content marking, creates DLP policies using built-in and custom sensitive information
-  types with regex patterns, deploys endpoint DLP rules to control file operations
-  on Windows and macOS devices, and monitors policy effectiveness through Activity
-  Explorer and DLP alert management. Uses PowerShell cmdlets and the Microsoft Graph
-  API for programmatic policy management. Activates for requests involving DLP policy
-  creation, sensitivity label configuration, data classification, endpoint data protection,
-  or Microsoft Purview compliance administration.
+description: 'Implements DLP policies using Microsoft Purview PowerShell cmdlets and
+  the Graph API to protect data across Exchange Online, SharePoint, OneDrive, Teams,
+  endpoints, and Power BI, including sensitivity labels, custom sensitive information
+  types with regex, endpoint DLP rules, and Activity Explorer monitoring. Use when
+  stopping PII/PHI/PCI exfiltration, configuring sensitivity labels, or investigating
+  DLP incidents for policy tuning.
 
   '
 domain: cybersecurity