- buildOutputFormatInstruction(schema): auto-generates frontmatter
format guide from Zod schema, injected at top of system prompt
- Adapter prepends deliverable format before role's systemPrompt
- buildThreadInput reordered: Task → Steps → Parent → Tools
- Scope reminder: 'Focus exclusively on YOUR role's deliverable'
- 8 tests for buildOutputFormatInstruction
Refs #351
Phase 2 of RFC #351 — adapter tries frontmatter first (zero LLM cost),
falls back to runtime.extract() when frontmatter is missing/invalid.
- tryFrontmatterMeta(): parse → validate → schema.safeParse
- Happy path stores body (no frontmatter) in CAS
- Fallback stores full raw in CAS + LLM extract
- 5 tests covering both paths
Refs #351
xiaoju