fix(ci): remove auto-commit of coverage badge

Remove the 'Commit coverage badge to main' step which fails due to
branch protection rules requiring verified signatures. The CI now:
- ✅ Runs all tests
- ✅ Checks coverage threshold (75%)
- ✅ Runs lint checks (errcheck)
- ✅ Builds successfully
- ✅ Generates coverage badge JSON (but doesn't auto-commit)

Badge can be updated manually if needed, but auto-commit is blocked
by repository rules (PR required, signed commits, mergegate check).

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: platinummonkey

.github/workflows/ci.yml

@@ -208,14 +208,8 @@ jobs:
 
           echo "Generated coverage badge: ${COVERAGE}% (${COLOR})"
 
-      - name: Commit coverage badge to main
-        if: github.ref == 'refs/heads/main' && github.event_name == 'push'
-        run: |
-          git config --local user.email "github-actions[bot]@users.noreply.github.com"
-          git config --local user.name "github-actions[bot]"
-          git add .github/badges/coverage.json
-          git diff --staged --quiet || git commit -m "chore: update coverage badge [skip ci]"
-          git push
+      # Note: Auto-committing badge disabled due to branch protection requiring signed commits
+      # Badge can be updated manually or via a separate workflow with appropriate permissions
 
       - name: Upload coverage artifacts
         uses: actions/upload-artifact@v4