model-tiering-convention

Model tiering convention for Orryx Group agents and subagents. Triggers when authoring a new subagent, configuring an agent's model, or deciding which model tier to use for a task. Defines haiku (explorer with permissionMode plan, doc-writer), sonnet (code-reviewer, test-writer, migration-writer, default delivery), and opus (security-reviewer, pr-investigator, deep-research, high-stakes review). Canonical Orryx convention; lifted from Triora.