feat(models): add Fable orchestration/delegation policy

[gsdevme]

Summary

Adds a new models.md topic that defines a model-delegation policy for Claude Code: treat the Fable session model as an orchestrator that spends its expensive tokens only on decomposition, judgment, and synthesis, and delegates real work to cheaper opus/sonnet worker agents via the Agent tool.

The topic is placed first in TOPIC_FILES, matching its "read first" framing, so it leads both the Claude @-imports in ~/.claude/CLAUDE.md and the concatenated Codex .agents/AGENTS.md.

Contents of models.md

• Scope note — explicitly Claude Code-only (Fable, the Agent tool, teammates); Codex still receives the file but is told it can ignore it.
• Delegation policy — opus as the default worker tier (preferring claude-opus-4-8), sonnet as the cheap tier for low-risk rote work.
• Reasoning effort per tier — Fable medium; opus and sonnet workers high.
• Delegation by task — routing for exploration/research, implementation, verification/review, and when Fable edits directly.
• Token rules — don't echo file contents/diffs, front-load paths and constraints into agent prompts, batch independent launches.

Changes

• models.md — new topic (Claude Code-scoped).
• Makefile — models.md prepended to TOPIC_FILES, driving both generated outputs.
• README.md — installed-layout tree updated to list models.md first.
• tests/apply.bats — the three hardcoded helpers (expected_claude, expected_agents, make_fixture_repo) updated to include models.md first. These were needed because the default-TOPIC_FILES tests exercise the real Makefile.

Test plan

• make apply renders both documents; ~/.claude/CLAUDE.md imports models.md as its first @-import and .agents/AGENTS.md opens with the # Model delegation content.
• make test — the full Bats suite (13 tests) passes.

🤖 Generated with Claude Code