The estate's one channel exit

Services that need to reach a person hand the message here instead of each
carrying a SendGrid key. Email goes to SendGrid, SMS to Twilio; whatsapp and
push answer 501 rather than pretending.

It binds loopback and the docker bridge only. An authenticated relay on the
public internet is an open spam relay the moment the token leaks, and that
token is copied into every consumer's environment.

The log names a channel, a redacted address and the provider's answer. Never
the subject, never the body.

.gitea/workflows/ci.yml

@@ -0,0 +1,28 @@
+# The delivery gate. Nothing reaches main that has not passed it.
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest        # label maps to act-22.04 on this estate's runner
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+
+      - name: Install
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements-dev.txt
+
+      - name: Test
+        run: python -m pytest -q
+
+      - name: The image has to build too
+        run: docker build -t channel-exit:ci .