fix(core): remove the build-audio-fx-runtime.ts stray resurrected by a main merge

An earlier merge with main brought this deleted file back (git's merge/delete
handling on an unchanged-on-one-side file); package.json already points at
build-inline-artifact.ts, so it sat unreachable and duplicating that file's
config, both of which fallow flagged.

packages/core/scripts/build-audio-fx-runtime.ts

@@ -1,50 +0,0 @@
-/** Build the injectable audio-FX runtime artifact from the canonical runtime. */
-
-import { mkdirSync, writeFileSync } from "node:fs";
-import { dirname, resolve } from "node:path";
-import { fileURLToPath } from "node:url";
-import { buildSync } from "esbuild";
-import { execFileSync } from "node:child_process";
-
-const thisDir = dirname(fileURLToPath(import.meta.url));
-const repoRoot = resolve(thisDir, "..");
-const entry = resolve(repoRoot, "stubs/audio-fx-runtime-entry.ts");
-const generatedDir = resolve(repoRoot, "src/generated");
-const outPath = resolve(generatedDir, "audio-fx-runtime-inline.ts");
-
-const result = buildSync({
-  entryPoints: [entry],
-  bundle: true,
-  write: false,
-  platform: "browser",
-  format: "iife",
-  target: ["es2020"],
-  minify: true,
-  legalComments: "none",
-});
-const iife = result.outputFiles[0]?.text ?? "";
-if (!iife) throw new Error("esbuild produced no output for audio-fx-runtime-entry.ts");
-
-mkdirSync(generatedDir, { recursive: true });
-writeFileSync(
-  outPath,
-  [
-    "// AUTO-GENERATED by scripts/build-audio-fx-runtime.ts - do not edit",
-    `const AUDIO_FX_RUNTIME_IIFE: string = ${JSON.stringify(iife)};`,
-    "",
-    "/** Returns the pre-built audio-FX runtime IIFE as a string constant. */",
-    "export function getAudioFxRuntimeScript(): string {",
-    "  return AUDIO_FX_RUNTIME_IIFE;",
-    "}",
-    "",
-  ].join("\n"),
-  "utf8",
-);
-
-try {
-  execFileSync("bun", ["x", "oxfmt", outPath], { stdio: "ignore" });
-} catch {
-  // Formatting is best effort when the generator runs in a minimal environment.
-}
-
-console.log(JSON.stringify({ event: "audio_fx_runtime_generated", outPath, bytes: iife.length }));