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/note/mod.rs

@@ -76,8 +76,11 @@ impl<'a> NoteView<'a> {
         note_cache: &'a mut NoteCache,
         img_cache: &'a mut ImageCache,
         note: &'a nostrdb::Note<'a>,
+        mut flags: NoteOptions,
     ) -> Self {
-        let flags = NoteOptions::actionbar | NoteOptions::note_previews;
+        flags.set_actionbar(true);
+        flags.set_note_previews(true);
+
         let parent: Option<NoteKey> = None;
         Self {
             ndb,
@@ -89,11 +92,6 @@ impl<'a> NoteView<'a> {
         }
     }
 
-    pub fn note_options(mut self, options: NoteOptions) -> Self {
-        *self.options_mut() = options;
-        self
-    }
-
     pub fn textmode(mut self, enable: bool) -> Self {
         self.options_mut().set_textmode(enable);
         self
@@ -287,7 +285,14 @@ impl<'a> NoteView<'a> {
                             .text_style(style.text_style()),
                     );
                 });
-                NoteView::new(self.ndb, self.note_cache, self.img_cache, &note_to_repost).show(ui)
+                NoteView::new(
+                    self.ndb,
+                    self.note_cache,
+                    self.img_cache,
+                    &note_to_repost,
+                    self.flags,
+                )
+                .show(ui)
             } else {
                 self.show_standard(ui)
             }
@@ -393,6 +398,7 @@ impl<'a> NoteView<'a> {
                                         self.ndb,
                                         self.img_cache,
                                         self.note_cache,
+                                        self.flags,
                                     )
                                 })
                                 .inner;
@@ -464,6 +470,7 @@ impl<'a> NoteView<'a> {
                                 self.ndb,
                                 self.img_cache,
                                 self.note_cache,
+                                self.flags,
                             );
 
                             if action.is_some() {