v0.1.6

Wording release, from scoring the prompt-1 agent eval runs against 0.1.5. The
templates and the suite are unchanged.

Changed

• SKILL.md fourth hard rule, the fourth non-negotiable in README.md and
  references/extension-auth.md: the extension-id allowlist is configuration,
  empty by default, with no id written into code. The key pair that pins the id
  belongs to the operator: code built from the skill ships the step that makes
  it and never commits a generated pair.
• SKILL.md quick start and references/data-model.md: host code goes in files
  of its own, the host's SQL included, for example
  db/process-mining/host.supabase.sql, rather than appended to a template.
• references/provenance.md records the additions.