fix: validateIntRange/FloatRange soportan rangos negativos

Bug: "-100-100" se parseaba como ["", "100", "100"] con splitScalar
Fix: Buscar el separador '-' que NO está al inicio del string

Ejemplos que ahora funcionan:
- "-100-100" → min=-100, max=100
- "-50-50" → min=-50, max=50
- "0-100" → min=0, max=100 (sin cambio)

Test añadido para rangos negativos.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/zcatconfig.zig

@@ -119,10 +119,18 @@ pub const ConfigVariable = struct {
         _ = self;
         const parsed = std.fmt.parseInt(i32, value, 10) catch return false;
 
-        // Parse "min-max"
+        // Parse "min-max" (soporta negativos, ej: "-100-100", "-50-50", "0-100")
-        var it = std.mem.splitScalar(u8, range, '-');
+        // Buscar el '-' separador: es el primero que NO está al inicio
-        const min_str = it.next() orelse return false;
+        const separator_pos = blk: {
-        const max_str = it.next() orelse return false;
+            const start: usize = if (range.len > 0 and range[0] == '-') 1 else 0;
+            for (range[start..], start..) |c, i| {
+                if (c == '-') break :blk i;
+            }
+            return false; // No encontró separador
+        };
+
+        const min_str = range[0..separator_pos];
+        const max_str = range[separator_pos + 1 ..];
 
         const min = std.fmt.parseInt(i32, min_str, 10) catch return false;
         const max = std.fmt.parseInt(i32, max_str, 10) catch return false;
@@ -134,10 +142,17 @@ pub const ConfigVariable = struct {
         _ = self;
         const parsed = std.fmt.parseFloat(f32, value) catch return false;
 
-        // Parse "min-max"
+        // Parse "min-max" (soporta negativos)
-        var it = std.mem.splitScalar(u8, range, '-');
+        const separator_pos = blk: {
-        const min_str = it.next() orelse return false;
+            const start: usize = if (range.len > 0 and range[0] == '-') 1 else 0;
-        const max_str = it.next() orelse return false;
+            for (range[start..], start..) |c, i| {
+                if (c == '-') break :blk i;
+            }
+            return false;
+        };
+
+        const min_str = range[0..separator_pos];
+        const max_str = range[separator_pos + 1 ..];
 
         const min = std.fmt.parseFloat(f32, min_str) catch return false;
         const max = std.fmt.parseFloat(f32, max_str) catch return false;
@@ -979,6 +994,26 @@ test "ConfigVariable validation - integer range" {
     try std.testing.expect(!int_var.validate("abc"));
 }
 
+test "ConfigVariable validation - negative integer range" {
+    // Rango con mínimo negativo: "-100-100"
+    const neg_var = ConfigVariable{
+        .name = "test_neg",
+        .config_key = "@test_neg",
+        .var_type = .integer,
+        .default = "0",
+        .auto_validate = "-100-100",
+        .description = "Test negative range",
+    };
+
+    try std.testing.expect(neg_var.validate("0"));
+    try std.testing.expect(neg_var.validate("-100"));
+    try std.testing.expect(neg_var.validate("100"));
+    try std.testing.expect(neg_var.validate("-50"));
+    try std.testing.expect(neg_var.validate("50"));
+    try std.testing.expect(!neg_var.validate("-101"));
+    try std.testing.expect(!neg_var.validate("101"));
+}
+
 test "ConfigVariable validation - enum" {
     const enum_var = ConfigVariable{
         .name = "test_enum",