feat(reflection): ✨ add ExtractTagValue and GetRelationshipInfo functions

* Implement ExtractTagValue to handle struct tag parsing.
* Introduce GetRelationshipInfo for extracting relationship metadata.
* Update tests to validate new functionality.
* Refactor related code for improved clarity and maintainability.

pkg/restheadspec/restheadspec_test.go

@@ -2,6 +2,8 @@ package restheadspec
 
 import (
 	"testing"
+
+	"github.com/bitechdev/ResolveSpec/pkg/common"
 )
 
 func TestParseModelName(t *testing.T) {
@@ -112,3 +114,88 @@ func TestNewStandardBunRouter(t *testing.T) {
 		t.Error("Expected router to be created, got nil")
 	}
 }
+
+func TestExtractTagValue(t *testing.T) {
+	tests := []struct {
+		name     string
+		tag      string
+		key      string
+		expected string
+	}{
+		{
+			name:     "Extract existing key",
+			tag:      "json:name;validate:required",
+			key:      "json",
+			expected: "name",
+		},
+		{
+			name:     "Extract key with spaces",
+			tag:      "json:name ; validate:required",
+			key:      "validate",
+			expected: "required",
+		},
+		{
+			name:     "Extract key at end",
+			tag:      "json:name;validate:required;db:column_name",
+			key:      "db",
+			expected: "column_name",
+		},
+		{
+			name:     "Extract key at beginning",
+			tag:      "primary:true;json:id;db:user_id",
+			key:      "primary",
+			expected: "true",
+		},
+		{
+			name:     "Key not found",
+			tag:      "json:name;validate:required",
+			key:      "db",
+			expected: "",
+		},
+		{
+			name:     "Empty tag",
+			tag:      "",
+			key:      "json",
+			expected: "",
+		},
+		{
+			name:     "Single key-value pair",
+			tag:      "json:name",
+			key:      "json",
+			expected: "name",
+		},
+		{
+			name:     "Key with empty value",
+			tag:      "json:;validate:required",
+			key:      "json",
+			expected: "",
+		},
+		{
+			name:     "Key with complex value",
+			tag:      "json:user_name,omitempty;validate:required,min=3",
+			key:      "json",
+			expected: "user_name,omitempty",
+		},
+		{
+			name:     "Multiple semicolons",
+			tag:      "json:name;;validate:required",
+			key:      "validate",
+			expected: "required",
+		},
+		{
+			name:     "BUN Tag",
+			tag:      "rel:has-many,join:rid_hub=rid_hub_child",
+			key:      "join",
+			expected: "rid_hub=rid_hub_child",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := common.ExtractTagValue(tt.tag, tt.key)
+			if result != tt.expected {
+				t.Errorf("ExtractTagValue(%q, %q) = %q; want %q", tt.tag, tt.key, result, tt.expected)
+			}
+		})
+	}
+}