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-log-integrity-with-blockchain/SKILL.md

@@ -1,10 +1,12 @@
 ---
 name: implementing-log-integrity-with-blockchain
-description: Build an append-only log integrity chain using SHA-256 hash chaining
-  for tamper detection. Each log entry is hashed with the previous entry's hash to
-  create a blockchain-like structure where modifying any entry invalidates all subsequent
-  hashes. Implements log ingestion, chain verification, tamper detection with pinpoint
-  identification, and periodic checkpoint anchoring to external timestamping services.
+description: >-
+  Builds an append-only log integrity chain using SHA-256 hash chaining, where
+  each entry incorporates the previous entry's hash so tampering invalidates all
+  subsequent hashes; covers log ingestion (syslog/JSON/plain text), chain
+  verification, pinpoint tamper detection, and checkpoint anchoring to external
+  timestamping services. Use for tamper-evident log storage for compliance or
+  forensics, or to verify whether log entries were altered.
 domain: cybersecurity
 subdomain: security-operations
 tags: