Finish bundled-template migration; simplify frontmatter; de-duplicate toolbar/menu

Completes the move off the external cookiecutter tool: drops
src/cookiecutter.rs and the cookiecutter_bin/Template-path setting now
that scaffolding always runs through the built-in MiniJinja engine,
and rewrites default_project_template() to walk up from the executable
without panicking when the bundled template can't be found. Rounds
out the snowflake template with the remaining 06-Revisions,
07-Final, 08-Covers and 09-Archive folders.

Simplifies the scene/chapter YAML frontmatter (drops type/word_count_min/
word_count_max in favor of status + a flat characters list) and updates
the new-file template, header parsing, outline, file list and Story
Bible editor to match.

Separately, de-duplicates the toolbar and menu bar: settings that only
existed as always-visible toolbar controls (draft marker, zero-pad,
spell-check toggle, dictionary picker) move into their Settings
windows, toolbar buttons that exactly duplicated a menu item are
dropped, and toolbar-only actions with no menu path (open project
folder, git sync/init) gain one under File. Also fixes two ambiguous
menu labels: the Story Bible editor now reads "Story Bible editor…"
next to "Story Bible…" in Tools instead of sharing a label with Edit,
and Settings' "New project…" is now "New-project settings…" so it
doesn't read like File's actual create action.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/story_bible_editor.rs

@@ -221,11 +221,15 @@ impl App {
         if !open {
             self.story_bible_editor_content.clear();
             self.story_bible_editor_path = None;
+            self.story_bible_editor_focused = false;
         }
     }
     
     /// Contents of the Story Bible editor window.
     fn story_bible_editor_contents(&mut self, ui: &mut egui::Ui, tree: &[BibleTreeNode]) {
+        // Set by the editor's text area below, read back out once the closures
+        // that borrow `self` have finished.
+        let mut focused = false;
         ui.horizontal(|ui| {
             // Left panel: Tree view (1/3 width)
             let tree_width = ui.available_width() / 3.0;
@@ -275,12 +279,12 @@ impl App {
                             .desired_rows(20);
                         
                         let response = ui.add(text_edit);
-                        
-                        // Handle keyboard shortcuts
-                        if response.has_focus() {
-                            // Ctrl+S to save - we'll handle this differently
-                            // since we can't mutate self directly from within the closure
-                        }
+
+                        // Recorded rather than acted on: the save needs `&mut
+                        // self`, which this closure is already borrowing to
+                        // draw with. `App::update` reads the flag next frame and
+                        // routes Ctrl+S here instead of to the manuscript.
+                        focused = response.has_focus();
                     });
                 
                 // Save button
@@ -298,6 +302,7 @@ impl App {
                 });
             });
         });
+        self.story_bible_editor_focused = focused;
     }
 
     /// Load a Story Bible item from the workspace.