fix(rules): remove empty segments from splitPipe output

Refactored splitPipe function to use forEachPipePart helper, which filters
out empty segments instead of including them in the result. Updated test
expectation to match the new behavior where empty parts between pipes
are no longer included.

internal/route/rules/on.go

@@ -570,45 +570,10 @@ func splitPipe(s string) []string {
 		return []string{}
 	}
 
-	result := make([]string, 0, 2)
-	quote := byte(0)
-	brackets := 0
-	start := 0
-
-	for i := 0; i < len(s); i++ {
-		switch s[i] {
-		case '\\':
-			// Skip escaped character.
-			if i+1 < len(s) {
-				i++
-			}
-		case '"', '\'', '`':
-			if quote == 0 && brackets == 0 {
-				quote = s[i]
-			} else if s[i] == quote {
-				quote = 0
-			}
-		case '(':
-			brackets++
-		case ')':
-			if brackets > 0 {
-				brackets--
-			}
-		case '|':
-			if quote == 0 && brackets == 0 {
-				result = append(result, strings.TrimSpace(s[start:i]))
-				start = i + 1
-			}
-		}
-	}
-
-	// drop trailing empty part.
-	if start < len(s) {
-		if part := strings.TrimSpace(s[start:]); part != "" {
-			result = append(result, part)
-		}
-	}
-
+	result := []string{}
+	forEachPipePart(s, func(part string) {
+		result = append(result, part)
+	})
 	return result
 }
 

internal/route/rules/on_internal_test.go

@@ -76,7 +76,7 @@ func TestSplitPipe(t *testing.T) {
 		{
 			name:  "empty_segments",
 			input: "rule1 || rule2 | | rule3",
-			want:  []string{"rule1", "", "rule2", "", "rule3"},
+			want:  []string{"rule1", "rule2", "rule3"},
 		},
 	}
 	for _, tt := range tests {