feat: open OneNote backup folders as notebooks

README.md

@@ -40,6 +40,9 @@ updates, removal, and the AppImage alternative.
   printouts, and OfficeMath equations on the freeform page canvas.
 - Imports complete `.onepkg` notebook exports through a guided, validated,
   on-disk process with progress and cancellation.
+- Opens manifest-free OneNote backup folders as one reconstructed notebook,
+  preserving nested directories as section groups and selecting the latest
+  dated copy of each section by default.
 - Keeps multiple notebooks open in one workspace with nested section groups,
   collapsible navigation, scoped search, complete result paths, and indexing of
   page titles and stored content.
@@ -60,10 +63,15 @@ updates, removal, and the AppImage alternative.
 ## Open Notebooks
 
 Use **Open Notebook Folder...** for a locally copied OneNote notebook directory,
-or **Open OneNote File...** for a standalone `.one` section. Additional notebook
-directories join the same searchable workspace without being moved. Notebook
-folders placed under the configurable default notebooks location open
-automatically on the next launch.
+or **Open OneNote File...** for a standalone `.one` section. Use **Open OneNote
+Backup Folder...** when a desktop backup contains dated `.one` section copies
+but no usable notebook table of contents. The backup opens as one notebook;
+folders become nested section groups, while the application menu can refresh
+the source or show every backup copy.
+
+Additional notebook directories join the same searchable workspace without
+being moved. Notebook and backup folders placed under the configurable default
+notebooks location open automatically on the next launch.
 
 ## Import a OneNote Package
 

crates/onenote-core/Cargo.toml

@@ -15,6 +15,7 @@ onenote_parser.workspace = true
 serde.workspace = true
 thiserror.workspace = true
 typed-path.workspace = true
+unicode-normalization.workspace = true
 uuid.workspace = true
 
 [dev-dependencies]

crates/onenote-core/examples/inspect-source.rs

@@ -1,5 +1,8 @@
-use onenote_core::OneNoteLoader;
+use onenote_core::{
+    BackupFolderLoader, BackupFolderOptions, BackupLoadControl, LoadedNotebook, OneNoteLoader,
+};
 use std::env;
+use std::path::Path;
 use std::process::ExitCode;
 
 fn main() -> ExitCode {
@@ -8,7 +11,7 @@ fn main() -> ExitCode {
         return ExitCode::from(2);
     };
 
-    match OneNoteLoader::default().load(&path) {
+    match load_source(Path::new(&path)) {
         Ok(loaded) => {
             let diagnostics = loaded
                 .notebook
@@ -48,3 +51,20 @@ fn main() -> ExitCode {
         }
     }
 }
+
+fn load_source(path: &Path) -> Result<LoadedNotebook, String> {
+    if !path.is_dir() {
+        return OneNoteLoader::default()
+            .load(path)
+            .map_err(|error| error.to_string());
+    }
+    let loader = BackupFolderLoader::default();
+    let control = BackupLoadControl::new();
+    let inspection = loader
+        .inspect(path, BackupFolderOptions::default(), &control, |_| {})
+        .map_err(|error| error.to_string())?;
+    loader
+        .load(inspection, &control, |_| {})
+        .map(|result| result.loaded)
+        .map_err(|error| error.to_string())
+}