Update arena chapter in the programming exercises book:

- Adjust page numbers in the PDF to reflect content changes.
- Correct exercise references and improve explanations for arena concepts.
- Enhance code examples for clarity and consistency.
- Add detailed descriptions for memory alignment and checkpoint functionalities.
- Include additional exercises focusing on heterogeneous records and performance comparisons.

.atl/.skill-registry.cache.json

@@ -1,3 +1,3 @@
 {
-  "fingerprint": "d3c21ce024c6ffe6e44e8dd85565ff6f6df97bc4"
+  "fingerprint": "60c5eae54c7e739d5e839304b313804bc547b807"
 }

.atl/skill-registry.md

@@ -6,6 +6,7 @@ Last updated: 2026-10-13
 
 ## Sources scanned
 
+- .opencode\skills
 - C:\Users\horacio\.agents\skills
 - C:\Users\horacio\.config\opencode\skills
 - C:\Users\horacio\.claude\skills
@@ -23,6 +24,7 @@ Last updated: 2026-10-13
 
 | Skill | Trigger / description | Scope | Path |
 | --- | --- | --- | --- |
+| `book-pdf` | Generar o regenerar los PDF de los capítulos del libro de C en dist/, con diseño consistente (resaltado de sintaxis, fuente mono para código, notas con fondo de color). Trigger - pdf, generar pdf, exportar capítulo, dist, md-to-pdf, print.css, "convertir a pdf", "rehacer pdf". | project | `C:\Users\horacio\Desarrollo\c-programming\.opencode\skills\book-pdf\SKILL.md` |
 | `branch-pr` | Create Gentle AI pull requests with issue-first checks. Trigger: creating, opening, or preparing PRs for review. | user | `C:\Users\horacio\.config\opencode\skills\branch-pr\SKILL.md` |
 | `chained-pr` | Trigger: PRs over 400 lines, stacked PRs, review slices. Split oversized changes into chained PRs that protect review focus. | user | `C:\Users\horacio\.config\opencode\skills\chained-pr\SKILL.md` |
 | `cognitive-doc-design` | Design docs that reduce cognitive load. Trigger: writing guides, READMEs, RFCs, onboarding, architecture, or review-facing docs. | user | `C:\Users\horacio\.config\opencode\skills\cognitive-doc-design\SKILL.md` |