Re-enable grouped coverage (simple workflow too resource intensive)

The simple single-run coverage workflow was crashing because running
all 110 tests with Xdebug coverage in one job is too memory/CPU intensive.
PHPUnit was stopping at test 63/110 without generating coverage.xml.

The grouped workflow was actually working correctly and successfully
generating coverage reports. It splits tests into 24 parallel groups,
which prevents resource exhaustion.

Changes:
- Re-enabled code-coverage-grouped.yml (working approach)
- Disabled code-coverage.yml (crashes on test 63/110)
- Grouped approach successfully generated 29.32% coverage before

This restores the working solution that properly handles test execution
with coverage in a resource-constrained CI environment.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: aristath

.github/workflows/code-coverage-grouped.yml

@@ -1,6 +1,14 @@
-name: Code Coverage (Grouped) - DISABLED
+name: Code Coverage (Grouped)
 
 on:
+  pull_request:
+    branches:
+      - develop
+      - main
+  push:
+    branches:
+      - develop
+      - main
   workflow_dispatch:
 
 # Cancels all previous workflow runs for the same branch that have not yet completed.

.github/workflows/code-coverage.yml

@@ -1,14 +1,6 @@
-name: Code Coverage
+name: Code Coverage - DISABLED (too resource intensive, use grouped)
 
 on:
-  pull_request:
-    branches:
-      - develop
-      - main
-  push:
-    branches:
-      - develop
-      - main
   workflow_dispatch:
 
 # Cancels all previous workflow runs for the same branch that have not yet completed.