Build the planner that turns a ModelMap into a Blueprint

Problem/Motivation

The scanner reads and decides nothing; the generator writes and decides nothing. Every decision — which bundles get which kinds of endpoint, which field maps to which key with which shape, which conventions apply — belongs to one component in between, so that the decisions are reviewable in one place and testable without touching the filesystem.

Proposed resolution

• A Planner service: ModelMap plus rules plus the site profile plus manual overrides in, Blueprint out.
• The Blueprint is data — the list of endpoints with their kind, path, plugin id and structure, and the structures with their properties — and nothing in it is a file path.
• The default rules written down as data too, not as conditionals: a bundle with a canonical route gets a detail endpoint, a bundle with more than N entities gets a listing, a vocabulary gets a term list.
• Manual overrides always win over the rules, and the Blueprint records which decision came from where — needed by the UI to show why an endpoint exists.
• Unit tests over fixture maps; no site, no database.

Remaining tasks

Everything.