fix(core): improve view robustness and axis management

`records_display` now returns `None` for out-of-bounds columns.

Added `try_axis_of` to `View` for non-panicking axis retrieval.

`cycle_axis` now uses `try_axis_of` to avoid panicking on unknown
categories.

Add regression tests for out-of-bounds access and unknown category cycling.

Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/gemma-4-26B-A4B-it-GGUF:UD-Q5_K_XL)

crates/improvise-core/src/view/layout.rs

@@ -182,11 +182,15 @@ impl GridLayout {
     }
 
     /// Get the display string for the cell at (row, col) in records mode.
-    /// Returns None for normal (non-records) layouts.
+    /// Returns None for normal (non-records) layouts and for out-of-bounds
+    /// rows/columns (symmetric with `cell_key`).
     pub fn records_display(&self, row: usize, col: usize) -> Option<String> {
         let records = self.records.as_ref()?;
         let record = records.get(row)?;
         let col_item = self.col_label(col);
+        if col_item.is_empty() {
+            return None;
+        }
         if col_item == "Value" {
             Some(record.1.to_string())
         } else {
@@ -806,6 +810,23 @@ mod tests {
         assert_eq!(last_value, "999", "new record should be the last row");
     }
 
+    /// Regression test for improvise-byz: `records_display` for an
+    /// out-of-bounds column called `col_label(col)`, which returns `""`;
+    /// `""` fails the `== "Value"` check, gets looked up as a category name
+    /// in the record (never found), and the function returned `Some("")` —
+    /// masking view/data mismatches. It must return `None`, symmetric with
+    /// `cell_key`, which explicitly returns `None` for an empty col label.
+    #[test]
+    fn records_display_out_of_bounds_col_returns_none() {
+        let mut wb = records_workbook();
+        let v = wb.active_view_mut();
+        v.set_axis("_Index", Axis::Row);
+        v.set_axis("_Dim", Axis::Column);
+        let layout = GridLayout::new(&wb.model, wb.active_view());
+        assert!(layout.is_records_mode());
+        assert_eq!(layout.records_display(0, layout.col_count()), None);
+    }
+
     fn coord(pairs: &[(&str, &str)]) -> CellKey {
         CellKey::new(
             pairs