Delete legacy emitter files replaced by component architecture

Removes the old procedural emitter implementation now fully replaced
by the Alloy JSX component-based emitter:
- graphql-emitter.ts (old emitter implementation)
- schema-emitter.ts (old schema-specific emitter)
- registry.ts (old type registry)
- type-maps.ts (old type mapping logic)
- emitter.test.ts (old emitter tests)

Replaces emitter.ts with a no-op stub so the package still conforms
to the TypeSpec emitter interface. The real component-based emitter
is added in the next PR in the chain.

Author: FionaBronwen

packages/graphql/src/emitter.ts

@@ -1,37 +1,6 @@
-import type { EmitContext, NewLine } from "@typespec/compiler";
-import { resolvePath } from "@typespec/compiler";
-import { createGraphQLEmitter } from "./graphql-emitter.js";
+import type { EmitContext } from "@typespec/compiler";
 import type { GraphQLEmitterOptions } from "./lib.js";
 
-const defaultOptions = {
-  "new-line": "lf",
-  "omit-unreachable-types": false,
-  strict: false,
-} as const;
-
-export async function $onEmit(context: EmitContext<GraphQLEmitterOptions>) {
-  const options = resolveOptions(context);
-  const emitter = createGraphQLEmitter(context, options);
-  await emitter.emitGraphQL();
-}
-
-export interface ResolvedGraphQLEmitterOptions {
-  outputFile: string;
-  newLine: NewLine;
-  omitUnreachableTypes: boolean;
-  strict: boolean;
-}
-
-export function resolveOptions(
-  context: EmitContext<GraphQLEmitterOptions>,
-): ResolvedGraphQLEmitterOptions {
-  const resolvedOptions = { ...defaultOptions, ...context.options };
-  const outputFile = resolvedOptions["output-file"] ?? "{schema-name}.graphql";
-
-  return {
-    outputFile: resolvePath(context.emitterOutputDir, outputFile),
-    newLine: resolvedOptions["new-line"],
-    omitUnreachableTypes: resolvedOptions["omit-unreachable-types"],
-    strict: resolvedOptions["strict"],
-  };
-}
+// Placeholder — the legacy emitter has been removed and the new
+// component-based emitter will be added in a follow-up PR.
+export async function $onEmit(_context: EmitContext<GraphQLEmitterOptions>) {}