chore(deps): bump codecov/codecov-action from 6 to 7

Matches Dependabot's java-llama.cpp #215 (and the equivalent per-repo bump);
applied on the shared feature branch so it rides the existing PR for this repo
instead of a separate Dependabot merge to main.

Author: claude

.github/workflows/publish.yml

@@ -813,7 +813,7 @@ jobs:
           format: jacoco
         continue-on-error: true
       - name: Codecov
-        uses: codecov/codecov-action@v6
+        uses: codecov/codecov-action@v7
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           files: target/site/jacoco/jacoco.xml