Prompt compiler: template system for reducing FEATURE_KNOWLEDGE duplication

[dean0x]

Summary

FEATURE_KNOWLEDGE content is currently duplicated across all orchestration skills and command files that pass it to agents. This was a deliberate choice for the initial implementation, but a template system would eliminate the duplication.

Proposed Solution

Introduce a compile-time template system:

• .template.md files with {{snippet:name}} placeholders
• Shared snippets in a shared/snippets/ directory
• A compile script that resolves snippets before distribution

Example

<!-- implement:orch/SKILL.template.md -->
## Phase 2: Load Feature Knowledge
{{snippet:feature-kb-loading}}

<!-- shared/snippets/feature-kb-loading.md -->
Load FEATURE_KNOWLEDGE from `.features/` index...

Context

• Deferred from PR feat: per-feature knowledge bases #193 (per-feature KB review)
• Current duplication is manageable (~6 files) but will grow as more skills consume FEATURE_KNOWLEDGE
• The same pattern would benefit KNOWLEDGE_CONTEXT loading

Acceptance Criteria

• Template files (.template.md) compile to final .md during npm run build
• Snippets live in shared/snippets/
• Build validates all {{snippet:*}} references resolve
• Existing commands and skills produce identical output after migration