feat(import): add Label field support for high-cardinality per-row data

Add support for Label-kind categories to handle high-cardinality
per-row fields like descriptions, IDs, and notes. These fields are
stored alongside regular categories but default to Axis::None and
are excluded from pivot category limits.

Changes:
- analyzer.rs: Label fields now default to accepted=true
- wizard.rs: Collect and process label fields during model building,
  attaching label values as coordinates for each cell
- category.rs: Add Label variant to CategoryKind enum
- types.rs: Add add_label_category() method and update category
  counting to only include Regular-kind categories

Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/Qwen3.5-35B-A3B-GGUF:Q5_K_M)

src/model/category.rs

@@ -59,11 +59,18 @@ pub enum CategoryKind {
     VirtualIndex,
     /// Items are the names of all regular categories + "Value".
     VirtualDim,
+    /// High-cardinality per-row field (description, id, note). Stored
+    /// alongside the data so it shows up in record/drill views, but
+    /// defaults to Axis::None and is excluded from pivot limits and the
+    /// auto Row/Column axis assignment.
+    Label,
 }
 
 impl CategoryKind {
-    pub fn is_virtual(&self) -> bool {
-        !matches!(self, CategoryKind::Regular)
+    /// True for user-managed pivot dimensions (what the category
+    /// count limit and auto axis assignment apply to).
+    pub fn is_regular(&self) -> bool {
+        matches!(self, CategoryKind::Regular)
     }
 }
 

src/model/types.rs

@@ -63,11 +63,11 @@ impl Model {
 
     pub fn add_category(&mut self, name: impl Into<String>) -> Result<CategoryId> {
         let name = name.into();
-        // Virtuals don't count against the regular category limit
+        // Only regular pivot categories count against the limit.
         let regular_count = self
             .categories
             .values()
-            .filter(|c| !c.kind.is_virtual())
+            .filter(|c| c.kind.is_regular())
             .count();
         if regular_count >= MAX_CATEGORIES {
             return Err(anyhow!("Maximum of {MAX_CATEGORIES} categories reached"));
@@ -86,6 +86,27 @@ impl Model {
         Ok(id)
     }
 
+    /// Add a Label-kind category: stored alongside regular categories so
+    /// records views can display it, but default to `Axis::None` and
+    /// excluded from the pivot-category count limit.
+    pub fn add_label_category(&mut self, name: impl Into<String>) -> Result<CategoryId> {
+        use crate::model::category::CategoryKind;
+        use crate::view::Axis;
+        let name = name.into();
+        if self.categories.contains_key(&name) {
+            return Ok(self.categories[&name].id);
+        }
+        let id = self.next_category_id;
+        self.next_category_id += 1;
+        let cat = Category::new(id, name.clone()).with_kind(CategoryKind::Label);
+        self.categories.insert(name.clone(), cat);
+        for view in self.views.values_mut() {
+            view.on_category_added(&name);
+            view.set_axis(&name, Axis::None);
+        }
+        Ok(id)
+    }
+
     pub fn category_mut(&mut self, name: &str) -> Option<&mut Category> {
         self.categories.get_mut(name)
     }