feat(03-04): Worker [assets] binding + one-command deploy + D-14 build-artifact gate

- wrangler.jsonc assets block serves ../web/dist; run_worker_first keeps /api/* + /telegram/* on the Worker (D-13)
- root npm run deploy = build theme → web → bot wrangler deploy + set-webhook (D-15); dev = build + wrangler dev --port 8787 --local (D-12)
- vite.config.ts dual-build: __ARAHARAH_HARNESS__ define keyed on --mode harness, separate dist/dist-harness outDirs
- main.ts guard unchanged; ambient constant declared once in web/src/vite-env.d.ts
- build-artifact.test.mjs BA1..BA6: zero CDN refs, self-hosted fonts, MapLibre worker, inlined style, no mock installer in ANY emitted file (HTML included)

web/vite.config.ts

@@ -1,23 +1,36 @@
 import { defineConfig } from "vite";
 
-export default defineConfig(({ mode }) => ({
-  base: "/",
-  // 03-03: the harness constant (declared ambient in main.ts; canonical home
-  // is web/src/vite-env.d.ts under plan 03-04) is REAL only in --mode harness
-  // builds and statically false everywhere else — with a bare ambient global
-  // referenced in main.ts, this define keeps plain `vite dev` from throwing a
-  // ReferenceError while the fallback mock install there still fires via
-  // import.meta.env.DEV. 03-04's dual-build config keys on the same mode.
-  define: {
-    __ARAHARAH_HARNESS__: JSON.stringify(mode === "harness"),
-  },
-  build: {
-    outDir: "dist",
-    emptyOutDir: true,
-    target: "es2022",
-  },
-  server: {
-    port: 5173,
-    strictPort: true,
-  },
-}));
+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,
+    },
+  };
+});