release: v0.2.4 里程碑快照（孤儿提交，无父；树 = dev 68362e5）

本批内容见 CHANGELOG.md 的 0.2.4 段。按 D41 用孤儿快照推 main，保留「公开史只有里程碑」的模型。

crates/app/src/appearance_bind.rs

@@ -0,0 +1,124 @@
+//! 「外观（高级）」四件的回调接线（从 `callbacks.rs` 拆出，守住单文件 ≤400 行）。
+//!
+//! 与 `wire_settings` 的分工：这个文件只负责 09 §101-104 的四个高级特性
+//! （背景图 / 面板半透明度 / 玻璃拟态 / 强调色）＋ 主题三态。
+//! 每个回调都是同一套动作：改 `state.prefs` → 下发到 Slint（`apply_*`）→ 落盘（`persist_settings`）→
+//! `sync()`。出厂全部关闭，所以「不碰设置页」时这里一次都不会触发。
+
+use std::rc::Weak;
+
+use crate::conv;
+use crate::ui_bind::Inner;
+
+/// 接主题三态与外观四件的回调。
+pub(crate) fn wire(ui: &crate::MainWindow, weak: &Weak<Inner>) {
+    {
+        let weak = weak.clone();
+        ui.on_theme_changed(move |mode| {
+            let Some(this) = weak.upgrade() else { return };
+            this.state.borrow_mut().prefs.theme = conv::theme_mode_from(mode);
+            this.apply_theme();
+            this.persist_settings();
+            this.sync();
+        });
+    }
+    // ── 09 §101-104「外观（高级）」四件（出厂全关，改动即刻落盘）────────
+    {
+        let weak = weak.clone();
+        ui.on_bg_image_enabled_changed(move |enabled| {
+            let Some(this) = weak.upgrade() else { return };
+            this.state.borrow_mut().prefs.appearance.bg_image_enabled = enabled;
+            this.apply_appearance();
+            this.persist_settings();
+            this.sync();
+        });
+    }
+    {
+        let weak = weak.clone();
+        ui.on_bg_image_changed(move |path| {
+            let Some(this) = weak.upgrade() else { return };
+            this.state.borrow_mut().prefs.appearance.bg_image = path.to_string();
+            this.apply_appearance();
+            this.persist_settings();
+            this.sync();
+        });
+    }
+    {
+        let weak = weak.clone();
+        ui.on_bg_fill_changed(move |fill| {
+            let Some(this) = weak.upgrade() else { return };
+            this.state.borrow_mut().prefs.appearance.bg_fill = conv::bg_fill_from(fill);
+            this.apply_appearance();
+            this.persist_settings();
+            this.sync();
+        });
+    }
+    {
+        let weak = weak.clone();
+        ui.on_bg_dim_changed(move |value| {
+            let Some(this) = weak.upgrade() else { return };
+            this.state.borrow_mut().prefs.appearance.bg_dim = value;
+            this.apply_appearance();
+            this.persist_settings();
+            this.sync();
+        });
+    }
+    {
+        let weak = weak.clone();
+        ui.on_panel_alpha_changed(move |value| {
+            let Some(this) = weak.upgrade() else { return };
+            this.state.borrow_mut().prefs.appearance.panel_alpha = value;
+            this.apply_appearance();
+            this.persist_settings();
+            this.sync();
+        });
+    }
+    {
+        let weak = weak.clone();
+        ui.on_glass_changed(move |enabled| {
+            let Some(this) = weak.upgrade() else { return };
+            this.state.borrow_mut().prefs.appearance.glass = enabled;
+            this.apply_appearance();
+            this.persist_settings();
+            this.sync();
+        });
+    }
+    {
+        let weak = weak.clone();
+        ui.on_accent_color_changed(move |text| {
+            let Some(this) = weak.upgrade() else { return };
+            let accepted = this.state.borrow_mut().prefs.appearance.set_accent(&text);
+            // 非法输入：只亮设置页的 warn 行，不改现状、不落盘
+            this.ui.set_accent_invalid(!accepted);
+            if accepted {
+                this.apply_appearance();
+                this.persist_settings();
+            }
+            this.sync();
+        });
+    }
+    {
+        let weak = weak.clone();
+        ui.on_accent_swatch_picked(move |index| {
+            let Some(this) = weak.upgrade() else { return };
+            let Ok(index) = usize::try_from(index) else {
+                return;
+            };
+            let accepted = this
+                .state
+                .borrow_mut()
+                .prefs
+                .appearance
+                .set_accent_preset(index);
+            if !accepted {
+                return;
+            }
+            let hex = this.state.borrow().prefs.appearance.accent_color.clone();
+            this.ui.set_accent_color(conv::accent_color(&hex));
+            this.ui.set_accent_invalid(false);
+            this.apply_appearance();
+            this.persist_settings();
+            this.sync();
+        });
+    }
+}