chore(ci): remove Codecov integration

Remove the Codecov upload step from CI workflow and the Codecov badge
from README.

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

Author: edelvalle

.github/workflows/ci.yml

@@ -98,8 +98,3 @@ jobs:
       env:
         DJHTMX_REDIS_URL: redis://localhost:6379/0
 
-    - name: Upload coverage reports to Codecov
-      uses: codecov/codecov-action@v5
-      with:
-        token: ${{ secrets.CODECOV_TOKEN }}
-      if: always()  # Upload coverage even if tests fail

README.md

@@ -1,7 +1,6 @@
 # djhtmx
 
 [![CI](https://github.com/edelvalle/djhtmx/actions/workflows/ci.yml/badge.svg)](https://github.com/edelvalle/djhtmx/actions/workflows/ci.yml)
-[![codecov](https://codecov.io/gh/edelvalle/djhtmx/branch/master/graph/badge.svg)](https://codecov.io/gh/edelvalle/djhtmx)
 
 Interactive UI Components for Django using [htmx](https://htmx.org)