Announce harness releases on Twitter (#341)

* Announce harness releases on Twitter

Mirror pydantic-ai's post-release tweet so a PyPI publish also posts to
the shared @pydantic account, keeping release visibility consistent
across the workspace. Version is read from the tag ref since the
release job emits no version output.

Requires the TWITTER_* secrets to be provisioned on this repo.

* Scope send-tweet secrets to the release environment

zizmor's secrets-outside-env audit fails the lint job because the tweet
job reads the TWITTER_* secrets without a dedicated environment. Bind it
to the release environment, matching the release job's convention for
secret-using jobs (the harness has no zizmor ignore config like
pydantic-ai does).

.github/workflows/main.yml

@@ -263,3 +263,44 @@ jobs:
 
       - run: uv build
       - uses: pypa/gh-action-pypi-publish@ed0c53931b1dc9bd32cbe73a98c7f6766f8a527e # v1.13.0
+
+  send-tweet:
+    name: Send tweet
+    needs: [release]
+    if: needs.release.result == 'success'
+    runs-on: ubuntu-latest
+    environment: release
+
+    steps:
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
+        with:
+          python-version: '3.12'
+      - name: Install dependencies
+        run: pip install tweepy==4.14.0
+      - name: Send tweet
+        shell: python
+        run: |
+          import os
+          import tweepy
+
+          client = tweepy.Client(
+              access_token=os.getenv("TWITTER_ACCESS_TOKEN"),
+              access_token_secret=os.getenv("TWITTER_ACCESS_TOKEN_SECRET"),
+              consumer_key=os.getenv("TWITTER_CONSUMER_KEY"),
+              consumer_secret=os.getenv("TWITTER_CONSUMER_SECRET"),
+          )
+          version = os.getenv("VERSION")
+          tweet = os.getenv("TWEET").format(version=version)
+          client.create_tweet(text=tweet)
+        env:
+          # The tag ref (e.g. "v1.2.3") already carries the leading v, so it is
+          # used verbatim in both the message and the release URL.
+          VERSION: ${{ github.ref_name }}
+          TWEET: |
+            Pydantic AI Harness {version} is out! 🎉
+
+            https://github.com/pydantic/pydantic-ai-harness/releases/tag/{version}
+          TWITTER_CONSUMER_KEY: ${{ secrets.TWITTER_CONSUMER_KEY }}
+          TWITTER_CONSUMER_SECRET: ${{ secrets.TWITTER_CONSUMER_SECRET }}
+          TWITTER_ACCESS_TOKEN: ${{ secrets.TWITTER_ACCESS_TOKEN }}
+          TWITTER_ACCESS_TOKEN_SECRET: ${{ secrets.TWITTER_ACCESS_TOKEN_SECRET }}