Drop the dead MODEL_SPEC.md reference

The schema description and the README both pointed at MODEL_SPEC.md in the
GitHub repository and called it the source of truth. That file does not exist
on main; these artifacts are the spec.

README.md

@@ -22,9 +22,9 @@ model repositories under
 
 ## Source of truth
 
-The human-readable spec lives at
-[`software-mansion/react-native-executorch:MODEL_SPEC.md`](https://github.com/software-mansion/react-native-executorch/blob/main/MODEL_SPEC.md).
-Edit that document first; the artifacts here are derived from it.
+The artifacts in this repository are the spec. Edit `config.schema.json` and
+`precisions.json` here, and treat them as authoritative for every published
+`config.json`.
 
 ## Versioning
 

config.schema.json

@@ -2,7 +2,7 @@
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "$id": "https://huggingface.co/software-mansion/react-native-executorch-spec/resolve/main/config.schema.json",
   "title": "react-native-executorch model config",
-  "description": "Per-backend config.json published alongside .pte files in software-mansion/react-native-executorch-* repositories. See https://github.com/software-mansion/react-native-executorch/blob/main/MODEL_SPEC.md for the full convention.",
+  "description": "Per-backend config.json published alongside .pte files in software-mansion/react-native-executorch-* repositories.",
   "type": "object",
   "required": [
     "$schema",