feat: add scramble flag for development text scrambling

This commit introduces a new scramble option to help reduce distractions
during development by scrambling text using rot13. When enabled via the
new `--scramble` flag, text displayed in various views is transformed,
making it easier to focus on layout and behavior without reading the
actual content.

App & Args Updates

  - Added a `scramble: bool` field to the main application state (in `app.rs`).

  - Extended argument parsing (in `args.rs`) to recognize the `--scramble` flag.

NoteOptions Enhancement

  - Introduced a new bit flag `scramble_text` in `NoteOptions` with
    corresponding setter/getter methods.

UI Adjustments

  - Propagated the scramble flag through note rendering functions across
    navigation, timeline, and note view modules.

  - Updated several UI components (e.g., in `nav.rs`, `route.rs`, and
    `contents.rs`) to accept and apply the new note options.

Rot13 Implementation

  - Implemented a helper function (`rot13`) to scramble text
    conditionally when the scramble option is enabled.

This feature is intended for development builds only, offering a way to
obscure text content during UI tweaks and testing.

Signed-off-by: William Casarin <jb55@jb55.com>

crates/notedeck_columns/src/ui/timeline.rs

@@ -388,10 +388,14 @@ impl<'a> TimelineTabView<'a> {
 
                 if !muted {
                     ui::padding(8.0, ui, |ui| {
-                        let resp =
-                            ui::NoteView::new(self.ndb, self.note_cache, self.img_cache, &note)
-                                .note_options(self.note_options)
-                                .show(ui);
+                        let resp = ui::NoteView::new(
+                            self.ndb,
+                            self.note_cache,
+                            self.img_cache,
+                            &note,
+                            self.note_options,
+                        )
+                        .show(ui);
 
                         if let Some(note_action) = resp.action {
                             action = Some(note_action)