feat: add crabrl-fork to workspace and fix taxonomy loading

- Add crabrl-fork to workspace Cargo.toml
- Update fiscal-xbrl-core to use local crabrl-fork
- Fix SurfaceFormulaOp enum: add Divide variant
- Fix SurfaceSignTransform enum: add Absolute variant
- Implement divide_formula_values function for SurfaceFormulaOp::Divide
- Implement Absolute sign transform handler
- Fix all taxonomy_loader and related tests to pass

rust/fiscal-xbrl-core/src/surface_mapper.rs

@@ -571,6 +571,7 @@ fn evaluate_formula_for_period(
     match formula.op {
         SurfaceFormulaOp::Sum => sum_formula_values(&values, formula.treat_null_as_zero),
         SurfaceFormulaOp::Subtract => subtract_formula_values(&values, formula.treat_null_as_zero),
+        SurfaceFormulaOp::Divide => divide_formula_values(&values, formula.treat_null_as_zero),
     }
 }
 
@@ -612,6 +613,33 @@ fn subtract_formula_values(values: &[Option<f64>], treat_null_as_zero: bool) ->
     Some(left - right)
 }
 
+fn divide_formula_values(values: &[Option<f64>], treat_null_as_zero: bool) -> Option<f64> {
+    if values.len() != 2 {
+        return None;
+    }
+
+    let left = if treat_null_as_zero {
+        values[0].unwrap_or(0.0)
+    } else {
+        values[0]?
+    };
+    let right = if treat_null_as_zero {
+        values[1].unwrap_or(0.0)
+    } else {
+        values[1]?
+    };
+
+    if right == 0.0 {
+        return None;
+    }
+
+    if !treat_null_as_zero && values.iter().all(|value| value.is_none()) {
+        return None;
+    }
+
+    Some(left / right)
+}
+
 pub fn merge_mapping_assignments(
     primary: &mut HashMap<String, MappingAssignment>,
     secondary: HashMap<String, MappingAssignment>,
@@ -831,6 +859,7 @@ fn transform_values(
                 period_id.clone(),
                 match sign_transform {
                     Some(SurfaceSignTransform::Invert) => value.map(|amount| -amount),
+                    Some(SurfaceSignTransform::Absolute) => value.map(|amount| amount.abs()),
                     None => *value,
                 },
             )