feat: nahual standalone — visores open-with sobre Llimphi (front-door, git-dep al monorepo)

Stack de visores extraído como front-door limpio: solo los crates nahual-*
(shell open-with + ~14 visores: texto/imagen/audio/video/svg/mapa/fuente/hex/
tabla/markdown/archivo/card/gallery/árbol + cores + meta-runtime). Todo lo
fundacional (discern, decoders media, fuentes content-addressed, hojas shared)
y Llimphi se consumen por git-dep del monorepo gioser.git — cero vendoring.
cargo check --workspace pasa (0 errores).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

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+# nahual
+
+> `nahual` (Nahuatl: *companion spirit*). Everyday "open-with" viewers, in Rust, on [Llimphi](https://gitea.gioser.net/sergio/llimphi).
+
+`nahual` is the set of viewers a desktop user expects — a file shell that dispatches the right viewer by content, plus viewers for text, images, audio, video, SVG, maps, fonts, hex, tables, markdown, archives and more. All render on the same GPU-accelerated Llimphi UI. A **meta-runtime** lets you define a new viewer from a JSON schema, with no Rust.
+
+## Run
+
+```sh
+cargo run --release -p nahual-shell-llimphi          # the open-with shell (dispatches by content)
+cargo run --release -p nahual-file-explorer-llimphi  # file tree
+cargo run --release -p nahual-image-viewer-llimphi   # image viewer
+cargo run --release -p nahual-text-viewer-llimphi    # text viewer
+```
+
+## Viewers
+
+`text` · `image` (PNG/JPEG/WebP) · `audio` · `video` · `svg` · `map` (geo) · `font` (TTF/OTF glyph outlines) · `hex` · `table` · `markdown` · `archive` (zip/tar) · `card` · `gallery` · `tree` — plus `nahual-viewer-core` / `nahual-source-core` / `nahual-thumb-core` and the `meta-runtime` + `meta-schema` libraries.
+
+## How dependencies work
+
+This is a clean front-door repo: it contains **only nahual's own crates**. Everything else is pulled as a git dependency —
+
+- the **Llimphi** UI framework → [`llimphi.git`](https://gitea.gioser.net/sergio/llimphi)
+- foundational crates (content discern, media decoders, content-addressed sources, shared leaves) → the [`gioser`](https://gitea.gioser.net/sergio/gioser) monorepo, the suite's source of truth.
+
+No vendoring, no duplication. First build clones those repos (cached afterwards).
+
+## Considerations
+
+- **Viewers, not editors.** To *edit* text use `nada`; to edit an image use `pineal`.
+- The media viewers decode AV1/Opus/FLAC/MP3/Vorbis/WebM natively (pure-Rust, no ffmpeg).
+- Cross-platform Llimphi UI (Linux/macOS/Windows); viewers also compile inside the Wawa kernel.
+
+## License
+
+MIT. Builds on [Llimphi](https://gitea.gioser.net/sergio/llimphi) and the [gioser](https://gitea.gioser.net/sergio/gioser) suite.