Ship a Logbuch skill and record token use

- docs/skill.md teaches a Claude what Logbuch is for, how an entry sounds
  and in which order the calls go, served at GET /api/v1/skill and as a
  download next to the spec and the guide
- a test keeps the skill from drifting: frontmatter, only endpoints that
  exist, house rules
- resolveClient stamps last_used_at, the access list said never used even
  after eleven entries

next.config.ts

@@ -11,6 +11,9 @@ const config: NextConfig = {
 	output: 'standalone',
 	outputFileTracingIncludes: {
 		'/api/v1/style-guide': ['./docs/style-guide.md'],
+		'/api/v1/skill': ['./docs/skill.md'],
+		'/admin/api/files/skill': ['./docs/skill.md'],
+		'/admin/api/files/style-guide': ['./docs/style-guide.md'],
 		'/': ['./node_modules/drizzle-orm/**'],
 		'/api/v1/media': sharpNative,
 		'/admin/media': sharpNative,