ci: publish models index via GitHub Releases (index-v* tags)

Runtimes must pin DEFAULT_INDEX_URL to a Release asset + sha256
sidecar — never raw.githubusercontent.com, never main. Workflow
release-index.yml stages models-index.yaml and its .sha256 on every
index-v* tag (or workflow_dispatch).

Author: Ronald Tse

.github/workflows/release-index.yml

@@ -0,0 +1,59 @@
+name: release-index
+
+# Publishes models.yaml as a GitHub Release asset (models-index.yaml +
+# .sha256 sidecar). Runtimes pin DEFAULT_INDEX_URL to a specific index-v*
+# tag — never raw.githubusercontent.com, never main.
+#
+# Trigger: push of an index-v* tag, or workflow_dispatch with a tag name.
+on:
+  push:
+    tags:
+      - "index-v*"
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: "Release tag (e.g. index-v1). Created if missing."
+        required: true
+        type: string
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Stage index assets
+        run: |
+          test -f models.yaml
+          cp models.yaml models-index.yaml
+          shasum -a 256 models-index.yaml | awk '{print $1 "  models-index.yaml"}' > models-index.yaml.sha256
+          echo "--- models-index.yaml.sha256 ---"
+          cat models-index.yaml.sha256
+          echo "--- head models-index.yaml ---"
+          head -20 models-index.yaml
+
+      - name: Create or update GitHub Release
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
+            tag="${{ inputs.tag }}"
+          else
+            tag="${GITHUB_REF_NAME}"
+          fi
+          case "$tag" in
+            index-v*) ;;
+            *) echo "tag must match index-v*: got '$tag'" >&2; exit 1 ;;
+          esac
+          if ! gh release view "$tag" >/dev/null 2>&1; then
+            gh release create "$tag" \
+              --title "$tag" \
+              --notes "Interscript ML model index ($tag). Runtimes resolve DEFAULT_INDEX_URL against this release asset + sha256 sidecar." \
+              --target "$GITHUB_SHA"
+          fi
+          gh release upload "$tag" models-index.yaml models-index.yaml.sha256 --clobber
+          echo "published $tag"
+          gh release view "$tag" --json assets --jq '.assets[].name'

models.yaml

@@ -1,20 +1,31 @@
-# interscript-ml model index — the stable URL every runtime resolves
-# model ids against (Ruby / TypeScript / Python implement the same
-# algorithm; this file is the contract).
+# interscript-ml model index — the contract every runtime resolves model
+# ids against (Ruby / TypeScript / Python implement the same algorithm).
+#
+# DISTRIBUTION: this file is published as a GitHub Release asset, never
+# via raw.githubusercontent.com. Tag shape: index-vN. Assets per release:
+#   models-index.yaml
+#   models-index.yaml.sha256
+# URL shape runtimes pin:
+#   https://github.com/interscript/interscript-ml/releases/download/index-vN/models-index.yaml
+# Cut a new index-vN tag (or dispatch release-index.yml) whenever the
+# index content changes in a way production consumers must see.
 #
 # Resolution algorithm (identical in all runtimes):
-#   1. resolve `id` in models.models
-#   2. prefer an installed cache copy at <cache_dir>/<id>/<filename>
+#   1. fetch the pinned index URL + its .sha256 sidecar; verify the body
+#   2. resolve `id` in models.models
+#   3. prefer an installed cache copy at <cache_dir>/<id>/<filename>
 #      whose whole-file sha256 matches `sha256`
-#   3. else download `url` to a temp file in the same directory,
+#   4. else download `url` (or assemble `parts`) to a temp file,
 #      verify sha256, atomically rename into place
-#   4. load the zip (IMF v1: member sha256 verification on load)
+#   5. load the zip (IMF v1: member sha256 verification on load)
 #
-# Overrides: SECRYST_INDEX (URL or path to an index like this one),
-# SECRYST_CACHE (cache directory; default ~/.cache/secryst).
+# Overrides: SECRYST_INDEX (URL or path to an index like this one —
+# HTTP sources must ship a sibling .sha256), SECRYST_CACHE (cache
+# directory; default ~/.cache/secryst or ~/.cache/interscript).
 #
 # Adding a model: it must have passed the WO03 gate (strict validation,
-# parity written into the zip) before an entry ships here.
+# parity written into the zip) before an entry ships here. Then cut a
+# new index-vN so runtimes pick it up on their next pin bump.
 version: 1
 models:
   khm-latn-1.0: