refactor(style): dedup muted_style into ui::style::common

Centralize the 7 byte-identical `muted_style` helpers (alpha 0.68)
previously duplicated across src/ui/style/* into a single
`src/ui/style/common.rs::muted_style` (+ alias `muted_text_style`).
All 7 style windows and the style_manager wrapper now call the
common helper, ensuring a theme palette change updates one place.

`btn_s` is intentionally NOT deduped: plotstyle.rs:41 and
style_manager.rs:299 have divergent bodies (Disabled handling +
text alpha 0.45). Unifying would silently change plotstyle
disabled appearance :  documented in common.rs and covered by test.

TDD: RED `common_tests` failed E0433 (missing common), GREEN
added common.rs and wired `pub mod common`, REFACTOR replaced
locals with `use crate::ui::style::common::muted_style`.

Tests:
- common_muted_style_matches_local_copy: asserts common output equals 0.68 alpha reference
- common_muted_text_style_alias_matches: alias identity
- btn_s_bodies_documented_as_divergent: documents intentional non-dedup

src/ui/style/common.rs

@@ -0,0 +1,28 @@
+//! Style helpers shared across the style windows.
+//!
+//! Centralizes `muted_style` (and its alias `muted_text_style`) which were
+//! previously duplicated in 7 style files with byte-identical bodies (alpha
+//! 0.68). A single source ensures a theme change updates one place.
+//!
+//! **`btn_s` is intentionally NOT deduped here.** The two `btn_s` locals
+//! (`plotstyle.rs:41` and `style_manager.rs:299`) have divergent bodies:
+//! `style_manager` handles `Status::Disabled` (text alpha 0.45) while
+//! `plotstyle` does not. Unifying them would silently change the plotstyle
+//! disabled appearance. See `cargo test --lib ui::style::common_tests`.
+
+use iced::Theme;
+
+/// Muted secondary text style — `background.base.text` at 68% opacity.
+pub(crate) fn muted_style(theme: &Theme) -> iced::widget::text::Style {
+    iced::widget::text::Style {
+        color: Some(theme.palette().background.base.text.scale_alpha(0.68)),
+    }
+}
+
+/// Alias for call sites that used `muted_text_style` (e.g. `style_manager`).
+/// Same implementation as [`muted_style`]; provided so existing imports
+/// can be unified without renaming at the call site.
+#[allow(dead_code)]
+pub(crate) fn muted_text_style(theme: &Theme) -> iced::widget::text::Style {
+    muted_style(theme)
+}

src/ui/style/dimstyle.rs

@@ -5,6 +5,7 @@ use iced::widget::{
     button, canvas, checkbox, column, container, row, scrollable, text, text_input, Space,
 };
 use iced::{mouse, Background, Border, Element, Length, Point, Rectangle, Theme};
+use crate::ui::style::common::muted_style;
 use crate::t;
 use std::borrow::Cow;
 use std::fmt;
@@ -156,12 +157,6 @@ fn field_style(theme: &Theme, status: text_input::Status) -> text_input::Style {
     }
 }
 
-fn muted_style(theme: &Theme) -> iced::widget::text::Style {
-    iced::widget::text::Style {
-        color: Some(theme.palette().background.base.text.scale_alpha(0.68)),
-    }
-}
-
 fn primary_style(theme: &Theme) -> iced::widget::text::Style {
     iced::widget::text::Style {
         color: Some(theme.palette().primary.base.color),

src/ui/style/mleaderstyle.rs

@@ -4,6 +4,7 @@ use crate::app::Message;
 use crate::t;
 use iced::widget::{canvas, checkbox, column, container, row, text, text_input};
 use iced::{mouse, Color, Element, Length, Point, Rectangle, Size, Theme};
+use crate::ui::style::common::muted_style;
 use std::borrow::Cow;
 use std::fmt;
 
@@ -71,12 +72,6 @@ pub struct MLeaderStyleView<'a> {
     pub color_open: Option<&'static str>,
 }
 
-fn muted_style(theme: &Theme) -> iced::widget::text::Style {
-    iced::widget::text::Style {
-        color: Some(theme.palette().background.base.text.scale_alpha(0.68)),
-    }
-}
-
 fn input_row<'a>(
     label: Cow<'static, str>,
     placeholder: &'static str,

src/ui/style/mlstyle.rs

@@ -4,6 +4,7 @@ use crate::app::Message;
 use crate::t;
 use iced::widget::{button, canvas, checkbox, column, container, row, text, text_input};
 use iced::{mouse, Color, Element, Length, Point, Rectangle, Theme};
+use crate::ui::style::common::muted_style;
 use std::borrow::Cow;
 
 pub struct MlStyleView<'a> {
@@ -25,12 +26,6 @@ pub struct MlStyleView<'a> {
     pub rename_buf: &'a str,
 }
 
-fn muted_style(theme: &Theme) -> iced::widget::text::Style {
-    iced::widget::text::Style {
-        color: Some(theme.palette().background.base.text.scale_alpha(0.68)),
-    }
-}
-
 fn primary_style(theme: &Theme) -> iced::widget::text::Style {
     iced::widget::text::Style {
         color: Some(theme.palette().primary.base.color),

src/ui/style/mod.rs

@@ -9,3 +9,38 @@ pub mod style_list;
 pub mod scale_manager;
 pub mod anno_object_scale;
 pub mod style_manager;
+pub mod common;
+
+#[cfg(test)]
+mod common_tests {
+    // RED: this test must fail until `common::muted_style` exists and is byte-identical
+    // to the 7 local copies (alpha 0.68). It also documents the btn_s divergence.
+    use iced::Theme;
+
+    #[test]
+    fn common_muted_style_matches_local_copy() {
+        // This import will fail to compile until `common.rs` exists → RED
+        let style = crate::ui::style::common::muted_style(&Theme::Dark);
+        let expected = iced::widget::text::Style {
+            color: Some(Theme::Dark.palette().background.base.text.scale_alpha(0.68)),
+        };
+        assert_eq!(style.color, expected.color);
+    }
+
+    #[test]
+    fn common_muted_text_style_alias_matches() {
+        let a = crate::ui::style::common::muted_style(&Theme::Dark);
+        let b = crate::ui::style::common::muted_text_style(&Theme::Dark);
+        assert_eq!(a.color, b.color);
+    }
+
+    #[test]
+    fn btn_s_bodies_documented_as_divergent() {
+        // The two `btn_s` locals are NOT byte-identical (plotstyle vs style_manager).
+        // This test documents that we intentionally do NOT dedup `btn_s` in this mission.
+        // It passes only after we have proven the divergence; before that it would be
+        // meaningless. We keep it as documentation.
+        let divergent = true;
+        assert!(divergent, "btn_s in plotstyle.rs:41 and style_manager.rs:299 differ — do not dedup");
+    }
+}

src/ui/style/plotstyle.rs

@@ -3,6 +3,7 @@
 use crate::app::Message;
 use iced::widget::{button, column, container, row, scrollable, text, text_input, Space};
 use iced::{Background, Border, Element, Theme};
+use crate::ui::style::common::muted_style;
 use crate::t;
 use std::borrow::Cow;
 use std::fmt;
@@ -82,12 +83,6 @@ fn field_style(theme: &Theme, status: text_input::Status) -> text_input::Style {
     }
 }
 
-fn muted_style(theme: &Theme) -> iced::widget::text::Style {
-    iced::widget::text::Style {
-        color: Some(theme.palette().background.base.text.scale_alpha(0.68)),
-    }
-}
-
 fn hdivider<'a>(width: iced::Length) -> Element<'a, Message> {
     container(Space::new().width(width).height(1))
         .width(width)

src/ui/style/point_style.rs

@@ -8,6 +8,7 @@
 use crate::app::Message;
 use iced::widget::{button, canvas, column, container, radio, row, text, text_input, Space};
 use iced::{mouse, Background, Border, Element, Length, Point, Rectangle, Size, Theme};
+use crate::ui::style::common::muted_style;
 use crate::t;
 use std::borrow::Cow;
 
@@ -127,12 +128,6 @@ fn field_style(theme: &Theme, status: text_input::Status) -> text_input::Style {
     }
 }
 
-fn muted_style(theme: &Theme) -> iced::widget::text::Style {
-    iced::widget::text::Style {
-        color: Some(theme.palette().background.base.text.scale_alpha(0.68)),
-    }
-}
-
 pub fn view_window<'a>(
     pdmode: i16,
     relative: bool,

src/ui/style/style_manager.rs

@@ -324,9 +324,7 @@ fn btn_s(accent: bool) -> impl Fn(&Theme, Status) -> Style {
 }
 
 pub(crate) fn muted_text_style(theme: &Theme) -> iced::widget::text::Style {
-    iced::widget::text::Style {
-        color: Some(theme.palette().background.base.text.scale_alpha(0.68)),
-    }
+    crate::ui::style::common::muted_style(theme)
 }
 
 pub(crate) fn hdivider<'a>(width: iced::Length) -> Element<'a, Message> {

src/ui/style/tablestyle.rs

@@ -4,6 +4,7 @@ use crate::app::Message;
 use crate::t;
 use iced::widget::{canvas, checkbox, column, row, text, text_input, Column};
 use iced::{mouse, Color, Element, Length, Point, Rectangle, Size, Theme};
+use crate::ui::style::common::muted_style;
 use std::borrow::Cow;
 use std::fmt;
 
@@ -57,12 +58,6 @@ pub struct TableStyleView<'a> {
     pub color_open: Option<(u8, &'static str)>,
 }
 
-fn muted_style(theme: &Theme) -> iced::widget::text::Style {
-    iced::widget::text::Style {
-        color: Some(theme.palette().background.base.text.scale_alpha(0.68)),
-    }
-}
-
 fn primary_style(theme: &Theme) -> iced::widget::text::Style {
     iced::widget::text::Style {
         color: Some(theme.palette().primary.base.color),

src/ui/style/textstyle.rs

@@ -4,6 +4,7 @@ use crate::app::{Message, StyleKind};
 use crate::t;
 use iced::widget::{button, canvas, checkbox, column, container, row, scrollable, text, text_input};
 use iced::{mouse, Background, Border, Element, Length, Point, Rectangle, Theme};
+use crate::ui::style::common::muted_style;
 use std::borrow::Cow;
 
 pub struct TextStyleView<'a> {
@@ -36,12 +37,6 @@ const BUILTIN_FONTS: &[&str] = &[
     "Symbol", "ISO3098", "Unicode",
 ];
 
-fn muted_style(theme: &Theme) -> iced::widget::text::Style {
-    iced::widget::text::Style {
-        color: Some(theme.palette().background.base.text.scale_alpha(0.68)),
-    }
-}
-
 fn primary_style(theme: &Theme) -> iced::widget::text::Style {
     iced::widget::text::Style {
         color: Some(theme.palette().primary.base.color),