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/taxonomy_loader.rs

@@ -15,6 +15,7 @@ fn default_include_in_output() -> bool {
 #[serde(rename_all = "snake_case")]
 pub enum SurfaceSignTransform {
     Invert,
+    Absolute,
 }
 
 #[derive(Debug, Deserialize, Clone)]
@@ -73,6 +74,7 @@ pub struct SurfaceFormula {
 pub enum SurfaceFormulaOp {
     Sum,
     Subtract,
+    Divide,
 }
 
 #[derive(Debug, Deserialize, Clone)]