Add keep-alive workflow to prevent Supabase free-tier pauses

Daily cron pings the REST API for qa_pairs which counts as activity and
resets the 7-day inactivity timer. Requires SUPABASE_URL and
SUPABASE_ANON_KEY repo secrets; the workflow fails fast if they are
missing rather than appearing to succeed silently.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: kutcode

.github/workflows/keep-alive.yml

@@ -0,0 +1,44 @@
+name: Keep Supabase awake
+
+# Free-tier Supabase projects pause after 7 days without API activity. This
+# workflow pings the project once a day so the timer never elapses. The ping
+# is a single SELECT against qa_pairs which counts as database activity.
+
+on:
+  schedule:
+    - cron: "0 12 * * *"  # daily at 12:00 UTC
+  workflow_dispatch:       # also runnable manually from the Actions tab
+
+jobs:
+  ping:
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+    steps:
+      - name: Validate secrets are configured
+        env:
+          SUPABASE_URL: ${{ secrets.SUPABASE_URL }}
+          SUPABASE_ANON_KEY: ${{ secrets.SUPABASE_ANON_KEY }}
+        run: |
+          if [ -z "$SUPABASE_URL" ] || [ -z "$SUPABASE_ANON_KEY" ]; then
+            echo "::error::SUPABASE_URL and SUPABASE_ANON_KEY must be set in repo Settings -> Secrets and variables -> Actions"
+            exit 1
+          fi
+
+      - name: Ping REST API
+        env:
+          SUPABASE_URL: ${{ secrets.SUPABASE_URL }}
+          SUPABASE_ANON_KEY: ${{ secrets.SUPABASE_ANON_KEY }}
+        run: |
+          STATUS=$(curl -sS -o /tmp/resp.txt -w "%{http_code}" \
+            "${SUPABASE_URL%/}/rest/v1/qa_pairs?limit=1" \
+            -H "apikey: ${SUPABASE_ANON_KEY}" \
+            -H "Authorization: Bearer ${SUPABASE_ANON_KEY}")
+          echo "HTTP ${STATUS}"
+          # 200 (rows returned) and 401 (RLS blocked, but the request still hit
+          # the database) both count as activity for pause-prevention purposes.
+          if [ "$STATUS" != "200" ] && [ "$STATUS" != "401" ]; then
+            echo "::error::Unexpected status ${STATUS} from Supabase"
+            cat /tmp/resp.txt
+            exit 1
+          fi
+          echo "Supabase project pinged successfully."