Rename the three-layer meta-model to the three-model pipeline #51

Parent

#35

What to build

The three layers are three models, each conforming to its own metamodel and joined by transformations. They are not metalevels, and "meta-model" reads as a metalevel claim to anyone trained on the course (Kühne: a metamodel needs two type-model-of steps; Bézivin and Gerbé: "the notion of a modeling layer is quite different from the notion of an abstraction layer").

The name follows. 0003's file name, chapter 00's heading and anchor, the overview diagram's file name, CONTEXT.md's section and the README call it the three-model pipeline, and "metamodel" is kept for language definitions. 0003's decision and its H1 are unchanged. The anchor and every pointer at it move in one commit, because lint:adrs resolves normative anchors. The coursework documents under emf/ (its README, emf/docs/architecture.md and its decision records) follow the same vocabulary.

Acceptance criteria

• "meta-model" appears only where it means a language definition.
• CONTEXT.md defines "three-model pipeline" and "metamodel".
• lint:adrs, node scripts/lint-adrs.ts emf and lint:links pass.

Blocked by

• Rewrite the em-dashes in the specification #26
• Rewrite the em-dashes in the decision records, registers, root documents and tooling #27