fix: add Codecov send-notifications step to trigger report processing

Codecov uploads succeed but ci_passed stays null — the GitHub App
webhook isn't signaling CI completion. Add explicit send-notifications
step so Codecov processes reports without waiting for the webhook.

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

Author: Fieldnote-Echo

.github/workflows/ci.yml

@@ -68,6 +68,13 @@ jobs:
           token: ${{ secrets.CODECOV_TOKEN }}
           files: coverage.xml
           fail_ci_if_error: false
+      - name: Notify Codecov
+        if: matrix.python-version == '3.12'
+        uses: codecov/codecov-action@671740ac38dd9b0130fbe1cec585b89eea48d3de # v5.5.2
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          run_command: send-notifications
+          fail_ci_if_error: false
 
   security:
     runs-on: ubuntu-latest