ci: add Codecov configuration for coverage reporting and update README with badge

Author: Dieg0Code

.codecov.yml

@@ -0,0 +1,26 @@
+# File .codecov.yml
+coverage:
+  status:
+    project:
+      default:
+        target: 80%  # Defines a minimum coverage threshold for approval
+        threshold: 2% # Allows a drop of up to 2% without failing
+    patch:
+      default:
+        target: 80%
+        threshold: 2%
+
+ignore:
+  - "examples/*"    # Ignore all content inside the examples folder
+  - "examples/**"   # Ensures all nested files are ignored
+
+comment:
+  layout: "diff, flags, files"
+  behavior: default
+
+parsers:
+  go:
+    partials_as_hits: true  # Counts partially covered lines as covered
+
+fixes:
+  - "::" # Fixes paths in reports to align with the repo structure

README.md

@@ -3,6 +3,7 @@
 
 [![Go Report Card](https://goreportcard.com/badge/github.com/Dieg0Code/syndicate-go)](https://goreportcard.com/report/github.com/Dieg0Code/syndicate-go)
 [![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/Dieg0Code/syndicate-go/ci.yml?branch=main)](https://github.com/Dieg0Code/syndicate-go/actions)
+[![codecov](https://codecov.io/github/Dieg0Code/syndicate-go/graph/badge.svg?token=FXYY1S9EP4)](https://codecov.io/github/Dieg0Code/syndicate-go)
 [![GoDoc](https://godoc.org/github.com/Dieg0Code/syndicate-go?status.svg)](https://pkg.go.dev/github.com/Dieg0Code/syndicate-go)
 [![License: Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 [![Release](https://img.shields.io/github/v/release/Dieg0Code/syndicate-go)](https://github.com/Dieg0Code/syndicate-go/releases)