fix: downgrade to codecov-action v4, update escapes pattern, ignore codecov.json, slim codecov config

codecov.yml

@@ -1,17 +1,3 @@
-coverage:
-  status:
-    project:
-      default:
-        target: 70%
-    patch:
-      default:
-        informational: true
-
 ignore:
   - "src/(?:bin|platform))/.+\\.rs"
   - "src/(?:app|events|formatter)\\.rs"
-
-comment:
-  layout: "reach,diff,flags,files,footer"
-  behavior: default
-  require_changes: false