docs(roadmap): document Gate A worker unbundled relative imports bug and 0.1.1 fix

ROADMAP.md

@@ -33,9 +33,32 @@ from the other side.
 - [~] **Gate A — a bare Vite page loads a prebuilt model and generates.**
       [examples/bare/](examples/bare/) exists and the GPU-free half is proven: `vite build` resolves
       through the `exports` map and splits into an entry chunk, the decode worker as its own chunk,
-      and the 6 MB WebLLM bundle as a lazy one. What remains is **one run in a WebGPU browser** to
-      confirm it generates. `npm run verify-consumer` already exercises a real install end to end,
-      short of the actual generation.
+      and the 6 MB WebLLM bundle as a lazy one.
+
+      **Broke on real-browser run: worker unbundled imports in production.**
+      When deployed to a static host (Hugging Face Spaces), `engine.load()` threw
+      `PACKAGE_INCOMPLETE`: *"The decode worker failed to load from .../assets/engine-worker-dJUbtWsb.js"*.
+
+      *Root cause:* Rollup's `new Worker(new URL(..., import.meta.url), { type: "module" })` handling
+      copies `engine-worker.js` verbatim as an asset chunk without bundling or rewriting its internal
+      ESM imports. The emitted worker still carries:
+      `import { WebWorkerMLCEngineHandler } from "../../vendor/web-llm.js"`
+      `import { WORKER_CONFIGURE } from "./constants.js"`
+      `import { DEFAULT_DECODE_STEPS } from "./multistep.js"`
+      On a static production deployment, these relative URLs resolve to 404s on the root domain,
+      killing the worker silently before handshake. `vite dev` hid this because `optimizeDeps.exclude`
+      served files directly from source where siblings exist. `test/consumer/verify.mjs` line 130
+      missed it because it asserted file *existence* (`assets.some(f => f.startsWith("engine-worker"))`),
+      never executing the worker in a browser.
+
+      *Remediation:*
+      - [x] **Demo workaround:** Pre-bundle `engine-worker.js` with `esbuild --bundle --format=esm` into a
+            standalone 6.58 MB file (`public/engine-worker.js`) with zero external imports, and pass explicit
+            `workerUrl: new URL("engine-worker.js", window.location.href)`.
+      - [ ] **Library permanent fix for 0.1.1:** In `build.mjs`, pre-bundle `engine-worker.js` into
+            a self-contained `dist/worker.bundle.js` at package build time. Point `DEFAULT_WORKER_URL`
+            at the bundle so zero consumer configuration or `workerUrl` is required. Update
+            `verify-consumer` with a headless browser fetch/execute assertion to prevent regressions.
 - [ ] **Gate A′ — the same page ingests a local folder.** `cache.put()` against the synthetic
       `local-model.invalid` key is proven only on an extension origin. Gates the *offline* route,
       not the library.