ci: two-stage trusted-publishing release workflow

.github/dependabot.yml

@@ -0,0 +1,14 @@
+version: 2
+updates:
+  # Keep GitHub Actions pinned to commit SHAs (supply-chain hardening) while
+  # still receiving updates: Dependabot opens a PR whenever a pinned action has
+  # a newer release, bumping the SHA and the trailing "# vX.Y.Z" comment.
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: weekly
+    groups:
+      # One consolidated PR per week instead of one per action.
+      github-actions:
+        patterns:
+          - "*"

.github/workflows/release.yml

@@ -0,0 +1,131 @@
+name: Release
+
+# Two-stage trusted-publishing pipeline, driven by git tags:
+#
+#   git tag v0.2.1.dev1 && git push origin v0.2.1.dev1   -> build + TestPyPI only
+#   git tag v0.2.1       && git push origin v0.2.1        -> build + TestPyPI + PyPI
+#
+# The SAME artifacts built once in `build` are promoted through both indexes, so
+# what lands on PyPI is byte-identical to what you smoke-tested on TestPyPI.
+#
+# Auth is OIDC trusted publishing (no API tokens stored). The manual approval
+# gates are GitHub Environment "required reviewers", configured in
+# Settings -> Environments (NOT in this file). The trusted-publisher registration
+# on each index must match, exactly:
+#   owner=thad0ctor  repo=Gefen-X  workflow=release.yml  environment=testpypi / pypi
+# Renaming this file breaks the OIDC handshake -- keep it release.yml.
+
+on:
+  push:
+    tags:
+      - "v*"
+
+# Only the publish jobs need privilege (id-token), and they widen it locally.
+permissions:
+  contents: read
+
+# Never cancel a release that is mid-flight (e.g. waiting on an approval gate).
+concurrency:
+  group: release-${{ github.ref }}
+  cancel-in-progress: false
+
+jobs:
+  build:
+    name: Build & verify artifacts
+    runs-on: ubuntu-latest
+    outputs:
+      version: ${{ steps.ver.outputs.version }}
+      prerelease: ${{ steps.ver.outputs.prerelease }}
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
+        with:
+          persist-credentials: false
+
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
+        with:
+          python-version: "3.12"
+          # No pip cache in this privileged publish workflow: GitHub caches are
+          # branch-scoped and writable by less-trusted runs, so a poisoned cache
+          # could taint the wheel uploaded to PyPI. Build tooling installs fast.
+
+      - name: Install build tooling
+        run: python -m pip install --upgrade pip build twine
+
+      - name: Build sdist + wheel
+        # Pure-Python build (kernels JIT at runtime), so no CUDA toolchain needed.
+        run: python -m build
+
+      - name: twine check
+        run: python -m twine check dist/*
+
+      - name: Verify tag matches package version
+        id: ver
+        # Guards against tagging vX.Y.Z while pyproject.toml still says the old
+        # version (the version is hard-coded there, so this is easy to forget).
+        run: |
+          TAG="${GITHUB_REF_NAME#v}"
+          WHEEL=$(ls dist/*.whl)
+          PKG_VER=$(basename "$WHEEL" | sed -E 's/^gefen_x-([^-]+)-py3.*/\1/')
+          echo "tag=$TAG  package=$PKG_VER"
+          if [ "$TAG" != "$PKG_VER" ]; then
+            echo "::error::Tag v$TAG does not match built package version $PKG_VER -- bump version in pyproject.toml"
+            exit 1
+          fi
+          echo "version=$PKG_VER" >> "$GITHUB_OUTPUT"
+          # PEP 440 prerelease markers (.devN / aN / bN / rcN) => TestPyPI only.
+          if echo "$PKG_VER" | grep -Eq '(\.dev|a|b|rc)[0-9]+$'; then
+            echo "prerelease=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "prerelease=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Upload artifacts
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: dist
+          path: dist/
+
+  testpypi:
+    name: Publish to TestPyPI (gate 1)
+    needs: build
+    runs-on: ubuntu-latest
+    # Approval gate #1: the `testpypi` environment's required reviewers.
+    environment:
+      name: testpypi
+      url: https://test.pypi.org/project/gefen-x/${{ needs.build.outputs.version }}/
+    permissions:
+      id-token: write   # mint the short-lived OIDC token; no stored secret
+    steps:
+      - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
+        with:
+          name: dist
+          path: dist/
+      - name: Publish to TestPyPI
+        uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # v1.14.0
+        with:
+          repository-url: https://test.pypi.org/legacy/
+          # A real release also passes through here; if that version was already
+          # tested on TestPyPI, don't hard-fail on the duplicate.
+          skip-existing: true
+
+  pypi:
+    name: Publish to PyPI (gate 2)
+    needs: [build, testpypi]
+    # Prerelease tags stop at TestPyPI; only clean vX.Y.Z tags reach PyPI.
+    if: needs.build.outputs.prerelease == 'false'
+    runs-on: ubuntu-latest
+    # Approval gate #2: the `pypi` environment's required reviewers.
+    environment:
+      name: pypi
+      url: https://pypi.org/project/gefen-x/${{ needs.build.outputs.version }}/
+    permissions:
+      id-token: write
+    steps:
+      - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
+        with:
+          name: dist
+          path: dist/
+      - name: Publish to PyPI
+        # Default index is PyPI. No skip-existing: re-releasing an existing
+        # version should hard-fail, not silently no-op.
+        uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # v1.14.0