Arah2/web/vite.config.ts

import { defineConfig } from "vite";

export default defineConfig(({ mode }) => {
  const isHarness = mode === "harness";
  return {
    base: "/",
    // 03-04 dual-build contract (the capture-harness fix, T-03-21):
    // `vite build --mode harness` emits to dist-harness/ WITH the mock
    // installer + fetch stubs; every other build emits to dist/ WITHOUT
    // them. The constant is REAL only in the harness mode and statically
    // false everywhere else — including plain `vite dev`, where this
    // define keeps main.ts's ambient reference from throwing a
    // ReferenceError while the fallback mock still fires via
    // import.meta.env.DEV.
    //
    // Vite replaces the IDENTIFIER textually at build time, so the
    // harness bundle compiles `if (VITE_HARNESS) installMockWebApp()`
    // down to `if (true) …`. The production build never defines it,
    // so the identifier is unreferenced and the branch is tree-shaken.
    //
    // The two builds must NEVER share an outDir: sharing one would make
    // them clobber each other and make the BA5 gate meaningless.
    define: {
      __ARAHARAH_HARNESS__: JSON.stringify(isHarness),
    },
    build: {
      outDir: isHarness ? "dist-harness" : "dist",
      emptyOutDir: true,
      target: "es2022",
    },
    server: {
      port: 5173,
      strictPort: true,
    },
  };
});