Drop the assembled-schema rebuild in favour of per-variant graphql-java forms

Phase 5 of firstclass-connection-types rebuilds the assembled GraphQLSchema via SchemaTransformer so directive-driven @asConnection carriers carry their rewritten return type and pagination args. The rebuild only runs at generate time and is never seen by the runtime (which reconstructs its schema from emitted <TypeName>Type.type() calls in GraphitronSchema.build()).

Alternative: skip the rebuild; rebuild each carrier’s parent GraphQLObjectType once via parent.transform(b → b.field(rewrittenField)) and stash it on the corresponding GraphitronType variant; emitters read per-variant schemaType() only. Already done for the synthesised types (Connection / Edge / PageInfo); this extends the pattern to rewritten parents.

Saves the two-step additionalType + SchemaTransformer dance (~80 lines of classifier code) and the bundle-coherence overhead. Costs the bundle’s "every type reference resolves on assembled.getType()`" invariant: any future build-time consumer that wants a coherent `GraphQLSchema (SDL printer for client schemas, an introspection-based validator, federation manifest emitter) would have to be re-engineered.

Worth picking up when a concrete signal pushes the trade, e.g. an emitter explicitly preferring per-variant graphql-java forms over name-keyed assembled.getType() lookups, or schema-rebuild edge cases turning into recurring debugging cost. Until then, the rebuild is paying its rent and Phase 5 stays.