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/timeline/route.rs

@@ -19,15 +19,13 @@ pub fn render_timeline_route(
     accounts: &mut Accounts,
     kind: &TimelineKind,
     col: usize,
-    textmode: bool,
+    mut note_options: NoteOptions,
     depth: usize,
     ui: &mut egui::Ui,
 ) -> Option<RenderNavAction> {
-    let note_options = {
-        let mut options = NoteOptions::new(kind == &TimelineKind::Universe);
-        options.set_textmode(textmode);
-        options
-    };
+    if kind == &TimelineKind::Universe {
+        note_options.set_hide_media(true);
+    }
 
     match kind {
         TimelineKind::List(_)
@@ -63,6 +61,7 @@ pub fn render_timeline_route(
                     col,
                     ui,
                     &accounts.mutefun(),
+                    note_options,
                 )
             } else {
                 // we render profiles like timelines if they are at the root
@@ -88,7 +87,7 @@ pub fn render_timeline_route(
             unknown_ids,
             img_cache,
             id.selected_or_root(),
-            textmode,
+            note_options,
             &accounts.mutefun(),
         )
         .id_source(egui::Id::new(("threadscroll", col)))
@@ -109,6 +108,7 @@ pub fn render_profile_route(
     col: usize,
     ui: &mut egui::Ui,
     is_muted: &MuteFun,
+    note_options: NoteOptions,
 ) -> Option<RenderNavAction> {
     let action = ProfileView::new(
         pubkey,
@@ -120,7 +120,7 @@ pub fn render_profile_route(
         img_cache,
         unknown_ids,
         is_muted,
-        NoteOptions::default(),
+        note_options,
     )
     .ui(ui);