fix numbering, text editor, and selection handling

Separate file/folder numbering by default, with shared numbering
option in the numbering rule popup. Text editor now loads names
from previous pipeline steps instead of originals, and uses
absolute position so it works correctly with any numbering mode.
Folders sort before files for consistent ordering. Spacebar
works in the text editor textarea without triggering drag.

crates/nomina-core/src/lib.rs

@@ -49,6 +49,7 @@ pub type Result<T> = std::result::Result<T, NominaError>;
 pub struct RenameContext {
     pub index: usize,
     pub total: usize,
+    pub absolute_index: usize,
     pub original_name: String,
     pub extension: String,
     pub path: PathBuf,
@@ -65,6 +66,7 @@ impl RenameContext {
         Self {
             index,
             total: 1,
+            absolute_index: index,
             original_name: String::new(),
             extension: String::new(),
             path: PathBuf::new(),

crates/nomina-core/src/pipeline.rs

@@ -33,14 +33,33 @@ impl Pipeline {
         self.steps.push(PipelineStep { rule, mode });
     }
 
-    pub fn preview(&self, files: &[crate::FileEntry]) -> Vec<PreviewResult> {
+    pub fn preview(&self, files: &[crate::FileEntry], shared_numbering: bool) -> Vec<PreviewResult> {
+        // precompute per-type counts and indices when using separate numbering
+        let dir_count = if shared_numbering { 0 } else { files.iter().filter(|f| f.is_dir).count() };
+        let file_count = if shared_numbering { 0 } else { files.iter().filter(|f| !f.is_dir).count() };
+        let mut dir_idx: usize = 0;
+        let mut file_idx: usize = 0;
+
         let results: Vec<PreviewResult> = files
             .iter()
             .enumerate()
             .map(|(i, file)| {
+                let (index, total) = if shared_numbering {
+                    (i, files.len())
+                } else if file.is_dir {
+                    let idx = dir_idx;
+                    dir_idx += 1;
+                    (idx, dir_count)
+                } else {
+                    let idx = file_idx;
+                    file_idx += 1;
+                    (idx, file_count)
+                };
+
                 let ctx = RenameContext {
-                    index: i,
-                    total: files.len(),
+                    index,
+                    total,
+                    absolute_index: i,
                     original_name: file.name.clone(),
                     extension: file.extension.clone(),
                     path: file.path.clone(),
@@ -183,7 +202,7 @@ mod tests {
         );
 
         let files = vec![make_file("IMG_001.jpg"), make_file("IMG_002.jpg")];
-        let results = pipeline.preview(&files);
+        let results = pipeline.preview(&files, true);
         assert_eq!(results[0].new_name, "photo-001.jpg");
         assert_eq!(results[1].new_name, "photo-002.jpg");
     }
@@ -215,7 +234,7 @@ mod tests {
         );
 
         let files = vec![make_file("IMG_001.jpg")];
-        let results = pipeline.preview(&files);
+        let results = pipeline.preview(&files, true);
         assert_eq!(results[0].new_name, "PHOTO-001.jpg");
     }
 
@@ -238,7 +257,7 @@ mod tests {
         );
 
         let files = vec![make_file("same.txt"), make_file("same.txt")];
-        let results = pipeline.preview(&files);
+        let results = pipeline.preview(&files, true);
         assert!(results[0].has_conflict);
         assert!(results[1].has_conflict);
     }

crates/nomina-core/src/rules/text_editor.rs

@@ -20,7 +20,7 @@ impl TextEditorRule {
 
 impl RenameRule for TextEditorRule {
     fn apply(&self, filename: &str, context: &RenameContext) -> String {
-        if let Some(name) = self.names.get(context.index) {
+        if let Some(name) = self.names.get(context.absolute_index) {
             if !name.is_empty() {
                 return name.clone();
             }