feat(ui): add show_cursor_outside_insert setting and Unicode‑aware wrapping; introduce grayscale‑high‑contrast theme

- Added `show_cursor_outside_insert` (default false) to `UiSettings` and synced it from config.
- Cursor rendering now follows `cursor_should_be_visible`, allowing visibility outside insert mode based on the new setting.
- Replaced `textwrap::wrap` with `wrap_unicode`, which uses Unicode break properties for proper CJK and emoji handling.
- Added `grayscale-high-contrast.toml` theme, registered it in theme loading, and updated README and tests.

crates/owlen-core/src/theme.rs

@@ -347,6 +347,10 @@ pub fn built_in_themes() -> HashMap<String, Theme> {
             "ansi_basic",
             include_str!("../../../themes/ansi-basic.toml"),
         ),
+        (
+            "grayscale-high-contrast",
+            include_str!("../../../themes/grayscale-high-contrast.toml"),
+        ),
         ("gruvbox", include_str!("../../../themes/gruvbox.toml")),
         ("dracula", include_str!("../../../themes/dracula.toml")),
         ("solarized", include_str!("../../../themes/solarized.toml")),
@@ -397,6 +401,7 @@ fn get_fallback_theme(name: &str) -> Option<Theme> {
         "monokai" => Some(monokai()),
         "material-dark" => Some(material_dark()),
         "material-light" => Some(material_light()),
+        "grayscale-high-contrast" => Some(grayscale_high_contrast()),
         _ => None,
     }
 }
@@ -831,6 +836,49 @@ fn material_light() -> Theme {
     }
 }
 
+/// Grayscale high-contrast theme
+fn grayscale_high_contrast() -> Theme {
+    Theme {
+        name: "grayscale_high_contrast".to_string(),
+        text: Color::Rgb(247, 247, 247),
+        background: Color::Black,
+        focused_panel_border: Color::White,
+        unfocused_panel_border: Color::Rgb(76, 76, 76),
+        user_message_role: Color::Rgb(240, 240, 240),
+        assistant_message_role: Color::Rgb(214, 214, 214),
+        tool_output: Color::Rgb(189, 189, 189),
+        thinking_panel_title: Color::Rgb(224, 224, 224),
+        command_bar_background: Color::Black,
+        status_background: Color::Rgb(15, 15, 15),
+        mode_normal: Color::White,
+        mode_editing: Color::Rgb(230, 230, 230),
+        mode_model_selection: Color::Rgb(204, 204, 204),
+        mode_provider_selection: Color::Rgb(179, 179, 179),
+        mode_help: Color::Rgb(153, 153, 153),
+        mode_visual: Color::Rgb(242, 242, 242),
+        mode_command: Color::Rgb(208, 208, 208),
+        selection_bg: Color::Rgb(240, 240, 240),
+        selection_fg: Color::Black,
+        cursor: Color::White,
+        placeholder: Color::Rgb(122, 122, 122),
+        error: Color::White,
+        info: Color::Rgb(200, 200, 200),
+        agent_thought: Color::Rgb(230, 230, 230),
+        agent_action: Color::Rgb(204, 204, 204),
+        agent_action_input: Color::Rgb(176, 176, 176),
+        agent_observation: Color::Rgb(153, 153, 153),
+        agent_final_answer: Color::White,
+        agent_badge_running_fg: Color::Black,
+        agent_badge_running_bg: Color::Rgb(247, 247, 247),
+        agent_badge_idle_fg: Color::Black,
+        agent_badge_idle_bg: Color::Rgb(189, 189, 189),
+        operating_chat_fg: Color::Black,
+        operating_chat_bg: Color::Rgb(242, 242, 242),
+        operating_code_fg: Color::Black,
+        operating_code_bg: Color::Rgb(191, 191, 191),
+    }
+}
+
 // Helper functions for color serialization/deserialization
 
 fn deserialize_color<'de, D>(deserializer: D) -> Result<Color, D::Error>
@@ -924,5 +972,6 @@ mod tests {
         assert!(themes.contains_key("default_dark"));
         assert!(themes.contains_key("gruvbox"));
         assert!(themes.contains_key("dracula"));
+        assert!(themes.contains_key("grayscale-high-contrast"));
     }
 }