docs(docs): add frontmatter to character-creation, content-architecture, and control-interaction workshops

Standardized YAML frontmatter on 5 files across 3 workshop directories.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/workshops/content-architecture/content-architecture-workshop-brief.md

@@ -1,3 +1,12 @@
+---
+title: "Workshop Brief: Content Architecture"
+description: "Design brief for three-tier content model, NPC generation, simulation budgets, and DLC architecture"
+type: workshop
+status: archived
+workshop: "content-architecture"
+created: 2026-02-11
+---
+
 # Workshop Brief: Content Architecture
 ## Filling a Galaxy Without Emptiness