fix(styles): reload Table/MLine buffers on structural ops, validate cell text style

style_new/copy/delete funneled through a load_style_bufs no-op for Table/MLine, leaving stale editor buffers pointed at the fresh style; both arms now route to the existing loaders. Table cell text-style typos persisted as dangling names; unknown names are now rejected with command-line feedback, keeping the buffer text for correction. Silent numeric parse-drops deliberately untouched (codebase-wide keep-old-valid norm). Tests: table_new_reloads_cell_buffers plus table_cell_unknown_text_style_is_rejected incl. retention assert (RED each verified by temporary revert). Full suite: 2048 passed / 0 failed / 25 ignored, zero warnings.

src/app/update/command.rs

@@ -4924,6 +4924,68 @@ mod tablestyle_ribbon_tests {
     }
 }
 
+#[cfg(test)]
+mod tablestyle_buffer_tests {
+    // #53: New/Copy/Delete must reload Table/MLine buffers (no stale edits
+    // into the fresh style), and cell text-style typos must not persist.
+    use crate::app::{OpenCADStudio, StyleKind};
+
+    #[test]
+    fn table_new_reloads_cell_buffers() {
+        let mut app = OpenCADStudio::new_for_test();
+        app.automation_op(r#"{"op":"new"}"#);
+        app.ts_cell_textstyle[0] = "STALE_SENTINEL".to_string();
+        app.style_new(StyleKind::Table);
+        assert_ne!(
+            app.ts_cell_textstyle[0], "STALE_SENTINEL",
+            "buffers must reload from the fresh style"
+        );
+    }
+
+    #[test]
+    fn table_cell_unknown_text_style_is_rejected() {
+        let mut app = OpenCADStudio::new_for_test();
+        app.automation_op(r#"{"op":"new"}"#);
+        let i = app.active_tab;
+        let style_name = app
+            .tabs[i]
+            .scene
+            .document
+            .objects
+            .values()
+            .find_map(|o| match o {
+                codec::objects::ObjectType::TableStyle(s) => Some(s.name.clone()),
+                _ => None,
+            })
+            .expect("fresh doc ships a table style");
+        app.tablestyle_selected = style_name.clone();
+        app.ts_cell_textstyle[0] = "NOPE".to_string();
+        let before = app.command_line.history.len();
+        let _ = app.on_table_style_cell_apply(0);
+        let cell_name = app.tabs[i]
+            .scene
+            .document
+            .objects
+            .values()
+            .find_map(|o| match o {
+                codec::objects::ObjectType::TableStyle(s) if s.name == style_name => {
+                    Some(s.data_row_style.text_style_name.clone())
+                }
+                _ => None,
+            })
+            .unwrap();
+        assert_ne!(cell_name, "NOPE", "dangling name must not persist");
+        assert_eq!(
+            app.ts_cell_textstyle[0], "NOPE",
+            "rejected text stays in the buffer for correction"
+        );
+        assert!(
+            app.command_line.history.len() > before,
+            "rejection must say something"
+        );
+    }
+}
+
 #[cfg(test)]
 mod plot_style_ctb_guard_tests {
     use crate::app::OpenCADStudio;