feat(aidd-context): cook researches a recipe, then applies it

[blafourcade]

The 12-cook skill authors recipes and stops there. A recipe nobody can research or run is a document.

Scope

• research — refine a target recipe against a checklist: fan out one agent per scouting angle (alternatives, new methods, coverage gaps, counter-intuitive wins, deprecations), then present three sorted buckets and a recommendation. Ephemeral, writes nothing. Mandatory before authoring.
• apply — execute an existing recipe against the project through an agent.
• Clarify the skill-authoring contract the skill was built against.

Acceptance criteria

• research never writes to disk.
• apply refuses a recipe that does not exist.
• Authoring a recipe without researching it first is refused.

Implemented in PR #301.