[Phase 6] ci: add scripts/publish-openapi.js and publish-openapi workflow

Closes leeworks-agents/api-company#100

- scripts/publish-openapi.js: Node.js script using only built-in modules
  (https, fs, path — no extra deps) that uploads each API's openapi.yaml
  to the RapidAPI Platform API via PUT multipart/form-data.
  - Reads RAPIDAPI_KEY/RAPIDAPI_PLATFORM_KEY from environment.
  - Skips silently per API if API ID / version ID not set.
  - Skips all uploads if RAPIDAPI_KEY not set (exits 0).
  - Exits non-zero on any HTTP error.
  - Logs: '✓ Published {api-name} spec to RapidAPI' on success.
  - Passes 'node --check' syntax validation.
- .gitea/workflows/publish-openapi.yaml: triggers on push to main when
  apis/*/openapi.yaml changes.
  - Runs Redocly CLI lint (fails pipeline on spec errors).
  - Detects changed specs via git diff.
  - Calls publish-openapi.js; no secrets = skip, not crash.

.gitea/workflows/publish-openapi.yaml

@@ -0,0 +1,58 @@
+# Validate and publish OpenAPI specs to RapidAPI when apis/*/openapi.yaml changes on main.
+# Requires secrets (configured once RapidAPI listings are live):
+#   RAPIDAPI_PLATFORM_KEY, RAPIDAPI_ZIP_API_ID, RAPIDAPI_ZIP_VERSION_ID,
+#   RAPIDAPI_HOLIDAYS_API_ID, RAPIDAPI_HOLIDAYS_VERSION_ID,
+#   RAPIDAPI_AQI_API_ID, RAPIDAPI_AQI_VERSION_ID
+#
+# If RAPIDAPI_PLATFORM_KEY is not set the publish step exits 0 with a skip message.
+
+name: Validate and Publish OpenAPI Specs
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'apis/*/openapi.yaml'
+
+jobs:
+  publish:
+    name: Lint and publish specs
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout (with history for diff)
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
+
+      - name: Set up Node.js 20
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Install Redocly CLI
+        run: npm install -g @redocly/cli@latest
+
+      - name: Lint OpenAPI specs
+        run: |
+          echo "Linting all OpenAPI specs..."
+          npx @redocly/cli lint apis/*/openapi.yaml
+
+      - name: Detect changed specs
+        id: changed
+        run: |
+          changed=$(git diff --name-only HEAD~1 HEAD | grep 'openapi\.yaml' || true)
+          echo "Changed specs: ${changed:-none}"
+          echo "files=${changed}" >> "$GITHUB_OUTPUT"
+
+      - name: Publish specs to RapidAPI
+        env:
+          RAPIDAPI_KEY: ${{ secrets.RAPIDAPI_PLATFORM_KEY }}
+          RAPIDAPI_ZIP_API_ID: ${{ secrets.RAPIDAPI_ZIP_API_ID }}
+          RAPIDAPI_ZIP_VERSION_ID: ${{ secrets.RAPIDAPI_ZIP_VERSION_ID }}
+          RAPIDAPI_HOLIDAYS_API_ID: ${{ secrets.RAPIDAPI_HOLIDAYS_API_ID }}
+          RAPIDAPI_HOLIDAYS_VERSION_ID: ${{ secrets.RAPIDAPI_HOLIDAYS_VERSION_ID }}
+          RAPIDAPI_AQI_API_ID: ${{ secrets.RAPIDAPI_AQI_API_ID }}
+          RAPIDAPI_AQI_VERSION_ID: ${{ secrets.RAPIDAPI_AQI_VERSION_ID }}
+        run: node scripts/publish-openapi.js