refactor(editor): hoist relative-alpha + over helpers into util

6 git_panel modules each duplicated fn alpha (RELATIVE: multiplies c.a*factor) and git_panel_empty duplicated over(). Hoisted to util::alpha / util::over (single source); locals now delegate. NOTE: align_toolbar::alpha SETS absolute alpha (Color{a,..}) — a different op (= Color::with_alpha), deliberately left separate. Part of atomic-sink Phase 0.4.

crates/op-editor-ui/src/util.rs

@@ -82,6 +82,29 @@ pub fn color_to_hex_with_alpha(c: Color) -> String {
     }
 }
 
+/// A colour at `factor` of its current alpha — the Rust analogue of a Tailwind
+/// `/NN` opacity modifier (e.g. `bg-muted/60`). RELATIVE: it MULTIPLIES the
+/// existing alpha. For an absolute set, use `Color::with_alpha` instead.
+pub fn alpha(c: Color, factor: f32) -> Color {
+    Color {
+        a: c.a * factor,
+        ..c
+    }
+}
+
+/// `top` (a translucent colour) composited over the opaque `base`, yielding an
+/// opaque colour — so a `bg-accent/30`-over-`bg-card` hover fill paints in a
+/// single pass.
+pub fn over(base: Color, top: Color) -> Color {
+    let a = top.a;
+    Color {
+        r: base.r * (1.0 - a) + top.r * a,
+        g: base.g * (1.0 - a) + top.g * a,
+        b: base.b * (1.0 - a) + top.b * a,
+        a: base.a,
+    }
+}
+
 /// Format a numeric property value for a panel input: drop a trailing `.0`
 /// for whole numbers, otherwise show two decimals.
 pub fn format_panel_number(value: f32) -> String {

crates/op-editor-ui/src/widgets/git_panel_clone.rs

@@ -245,8 +245,5 @@ impl GitPanel<'_> {
 
 /// A colour at `factor` of its current alpha (Tailwind `/NN`).
 fn alpha(c: Color, factor: f32) -> Color {
-    Color {
-        a: c.a * factor,
-        ..c
-    }
+    crate::util::alpha(c, factor)
 }

crates/op-editor-ui/src/widgets/git_panel_empty.rs

@@ -347,21 +347,12 @@ impl GitPanel<'_> {
 /// A colour at `factor` of its current alpha — the Rust analogue of a
 /// Tailwind `/NN` opacity modifier (e.g. `bg-muted/60`).
 fn alpha(c: Color, factor: f32) -> Color {
-    Color {
-        a: c.a * factor,
-        ..c
-    }
+    crate::util::alpha(c, factor)
 }
 
 /// `top` (a translucent colour) composited over the opaque `base`,
 /// yielding an opaque colour — so a `bg-accent/30`-over-`bg-card` hover
 /// fill paints in a single pass.
 fn over(base: Color, top: Color) -> Color {
-    let a = top.a;
-    Color {
-        r: base.r * (1.0 - a) + top.r * a,
-        g: base.g * (1.0 - a) + top.g * a,
-        b: base.b * (1.0 - a) + top.b * a,
-        a: base.a,
-    }
+    crate::util::over(base, top)
 }

crates/op-editor-ui/src/widgets/git_panel_menus.rs

@@ -898,10 +898,7 @@ impl GitPanel<'_> {
 
 /// A colour at `factor` of its current alpha (Tailwind `/NN`).
 fn alpha(c: Color, factor: f32) -> Color {
-    Color {
-        a: c.a * factor,
-        ..c
-    }
+    crate::util::alpha(c, factor)
 }
 
 /// Rough rendered width of a 12px label without a backend — CJK glyphs

crates/op-editor-ui/src/widgets/git_panel_ready.rs

@@ -963,10 +963,7 @@ impl GitPanel<'_> {
 
 /// A colour at `factor` of its current alpha (Tailwind `/NN`).
 fn alpha(c: Color, factor: f32) -> Color {
-    Color {
-        a: c.a * factor,
-        ..c
-    }
+    crate::util::alpha(c, factor)
 }
 
 /// The first whitespace-delimited token of an author name — TS

crates/op-editor-ui/src/widgets/git_panel_ssh_keys.rs

@@ -174,8 +174,5 @@ impl GitPanel<'_> {
 
 /// A colour at `factor` of its current alpha (Tailwind `/NN`).
 fn alpha(c: Color, factor: f32) -> Color {
-    Color {
-        a: c.a * factor,
-        ..c
-    }
+    crate::util::alpha(c, factor)
 }

crates/op-editor-ui/src/widgets/git_panel_tracked_picker.rs

@@ -385,8 +385,5 @@ fn popup_anchor(popup: Rect) -> Rect {
 
 /// A colour at `factor` of its current alpha (Tailwind `/NN`).
 fn alpha(c: Color, factor: f32) -> Color {
-    Color {
-        a: c.a * factor,
-        ..c
-    }
+    crate::util::alpha(c, factor)
 }