UniGPT provider for pi

Native /login with a verified API key, automatic model discovery from
UniGPT's /models endpoint, per-deployment deployment-id headers, and
model metadata from pi's bundled catalog.

.github/workflows/ci.yml

@@ -0,0 +1,27 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node: [22, 24]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 11
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node }}
+          cache: pnpm
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm run ci