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/nav.rs

@@ -16,7 +16,7 @@ use crate::{
         column::NavTitle,
         configure_deck::ConfigureDeckView,
         edit_deck::{EditDeckResponse, EditDeckView},
-        note::{PostAction, PostType},
+        note::{NoteOptions, PostAction, PostType},
         profile::EditProfileView,
         support::SupportView,
         RelayView, View,
@@ -243,6 +243,13 @@ fn render_nav_body(
     col: usize,
     inner_rect: egui::Rect,
 ) -> Option<RenderNavAction> {
+    let note_options = {
+        let mut options = NoteOptions::default();
+        options.set_textmode(app.textmode);
+        options.set_scramble_text(app.scramble);
+        options
+    };
+
     match top {
         Route::Timeline(kind) => render_timeline_route(
             ctx.ndb,
@@ -253,7 +260,7 @@ fn render_nav_body(
             ctx.accounts,
             kind,
             col,
-            app.textmode,
+            note_options,
             depth,
             ui,
         ),
@@ -310,6 +317,7 @@ fn render_nav_body(
                         ctx.img_cache,
                         &note,
                         inner_rect,
+                        note_options,
                     )
                     .id_source(id)
                     .show(ui)
@@ -345,6 +353,7 @@ fn render_nav_body(
                     draft,
                     &note,
                     inner_rect,
+                    note_options,
                 )
                 .id_source(id)
                 .show(ui)
@@ -366,6 +375,7 @@ fn render_nav_body(
                 ctx.note_cache,
                 kp,
                 inner_rect,
+                note_options,
             )
             .ui(&txn, ui);