[RNE Rewrite] docs: rewrite documentation

.cspell-wordlist.txt

@@ -350,3 +350,17 @@ phonemizes
 həlˈoʊ
 NSURL
 backgrounding
+memcpy
+autoregressive
+dispatchable
+embedder
+embedders
+Embedder
+Pretraining
+Unigram
+Unigrams
+subword
+wordpiece
+anonymization
+gapless
+Feedforward

.gitattributes

@@ -1,3 +1,8 @@
 *.pbxproj -text
 # specific for windows script files
-*.bat text eol=crlf
+*.bat text eol=crlf
+
+# Linguist vendoring for accurate language statistics and cloc
+third-party/** linguist-vendored
+**/third-party/** linguist-vendored
+packages/react-native-executorch/third-party/** linguist-vendored

docs/docs/01-fundamentals/02-downloading-models.md

@@ -0,0 +1,127 @@
+---
+title: Downloading Models
+slug: /fundamentals/downloading-models
+description: 'How model files reach the device — the pre-exported model registry, automatic download and caching in hooks, and the imperative download API with progress and cancellation.'
+keywords:
+  [
+    react native executorch,
+    download model,
+    model cache,
+    useResourceDownload,
+    download,
+    on-device ai,
+    pte,
+  ]
+---
+
+# Downloading Models
+
+A model is one or more files — the `.pte` program, and often a tokenizer,
+phonemizer, or label map alongside it — that have to be present on the device
+before inference can run. React Native ExecuTorch downloads those files for you
+and caches them persistently, so in most apps you never touch the filesystem
+directly: you point a pipeline at a model and the library fetches whatever isn't
+already cached.
+
+## Where models come from
+
+A model source is either remote or local:
+
+- **Pre-exported models** live in our
+  [HuggingFace collection](https://huggingface.co/software-mansion/collections) and
+  are addressed through the
+  [`models`](../06-api-reference/variables/models.md) registry. Each entry bundles
+  every file a pipeline needs behind one object — for example
+  `models.classification.EFFICIENTNET_V2_S.XNNPACK_FP32` resolves to the model and
+  its label assets. This registry is the single source of truth for the tuned,
+  ready-to-run models.
+- **Your own models** are plain URLs or local paths — a file bundled with the app,
+  a `file://` path, or a URL on your own host — as long as the model's schema
+  matches the pipeline (see
+  [Exporting Custom Models](../03-core-and-advanced/07-exporting-custom-models.md)).
+
+Local paths are always passed through untouched; only `http(s)` URLs are ever
+downloaded.
+
+## Automatic downloading with hooks
+
+The `use<Task>` hooks and the
+[`useResourceDownload`](../06-api-reference/functions/useResourceDownload.md) hook
+download and cache a model's files automatically. Pass a config; the hook fetches
+anything not already cached, reports progress, and hands back the same config with
+every URL replaced by its local path.
+
+```typescript
+import { useResourceDownload, models } from 'react-native-executorch';
+
+function Example() {
+  const { resource, downloadProgress, downloadError } = useResourceDownload(
+    models.classification.EFFICIENTNET_V2_S.XNNPACK_FP32
+  );
+
+  // resource is undefined until the download resolves, then mirrors the config
+  // with local file paths, ready to hand to a pipeline.
+}
+```
+
+Both hooks accept
+[`ResourceOptions`](../06-api-reference/type-aliases/ResourceOptions.md):
+
+- **`preventLoad`** — skip the download entirely (and reset state), for deferring a
+  fetch until the user opts in.
+- **`forceDownload`** — re-fetch even when cached, to replace a corrupted file or
+  pick up a model that changed behind a stable URL.
+
+## Imperative downloading
+
+When you're not in a component — a background task, a custom pipeline, a
+preloading step — use the imperative
+[`download`](../06-api-reference/functions/download.md) function. It takes a URL,
+or any nested object/array of them (typically a whole model config), downloads
+every remote leaf, and resolves with the same value with URLs replaced by local
+paths — ready to pass straight to a `create<Task>` factory:
+
+```typescript
+import { download, models } from 'react-native-executorch';
+
+const model = await download(models.classification.EFFICIENTNET_V2_S.XNNPACK_FP32, {
+  onProgress: (p) => console.log(`${Math.round(p * 100)}%`),
+});
+
+// `model` now holds local paths; hand it to a pipeline factory
+```
+
+[`DownloadOptions`](../06-api-reference/interfaces/DownloadOptions.md) covers the
+common needs:
+
+- **`onProgress(p)`** — overall progress in `[0, 1]`, weighted by each file's byte
+  size so a large model isn't reported the same as a small tokenizer.
+- **`signal`** — an `AbortSignal` to cancel. On iOS the bytes fetched so far are
+  kept, so a later download of the same source resumes rather than restarts.
+- **`forceDownload`** — re-download even when cached.
+
+## Caching behavior
+
+Downloads go to a persistent cache keyed by URL, and this is what keeps repeat
+launches fast:
+
+- A file that is already cached resolves immediately — no network round trip.
+- Concurrent downloads of the same URL are deduplicated into one transfer.
+- On Android, fetching goes through the system DownloadManager, which handles
+  multi-gigabyte files and continues in the background; on iOS it streams and
+  resumes an interrupted download from where it stopped.
+
+Use `forceDownload` to bypass the cache and replace a file. Otherwise, downloading
+the same model again is effectively free.
+
+## Where to go next
+
+- [Getting Started](./01-getting-started.md) — install the library and run your first model.
+- [Exporting Custom Models](../03-core-and-advanced/07-exporting-custom-models.md) — bring your own `.pte` and match a pipeline.
+- [Models & Tensors](../03-core-and-advanced/02-models-and-tensors.md) — load a downloaded `.pte` directly with the lower-level API.
+
+### API reference
+
+- [`download()`](../06-api-reference/functions/download.md) · [`DownloadOptions`](../06-api-reference/interfaces/DownloadOptions.md)
+- [`useResourceDownload()`](../06-api-reference/functions/useResourceDownload.md) · [`ResourceOptions`](../06-api-reference/type-aliases/ResourceOptions.md)
+- [`models`](../06-api-reference/variables/models.md)