Feat: begin sample explorer overhaul

src/input/mouse.rs

@@ -211,6 +211,21 @@ fn handle_scroll(ctx: &mut InputContext, col: u16, row: u16, term: Rect, up: boo
         return;
     }
 
+    // Scroll over side panel area
+    if ctx.app.panel.visible && ctx.app.panel.side.is_some() {
+        let (_main_area, side_area) = panel_split(body);
+        if contains(side_area, col, row) {
+            if let Some(crate::state::SidePanel::SampleBrowser(state)) = &mut ctx.app.panel.side {
+                if up {
+                    state.move_up();
+                } else {
+                    state.move_down();
+                }
+            }
+            return;
+        }
+    }
+
     match ctx.app.page {
         Page::Main => {
             if up {
@@ -356,25 +371,60 @@ fn handle_footer_click(ctx: &mut InputContext, col: u16, row: u16, footer: Rect)
 
 // --- Body ---
 
-fn handle_body_click(ctx: &mut InputContext, col: u16, row: u16, body: Rect, kind: ClickKind) {
-    // Account for side panel splitting
-    let page_area = if ctx.app.panel.visible && ctx.app.panel.side.is_some() {
-        if body.width >= 120 {
-            let panel_width = body.width * 35 / 100;
-            let [main, _side] =
-                Layout::horizontal([Constraint::Fill(1), Constraint::Length(panel_width)])
-                    .areas(body);
-            main
-        } else {
-            let panel_height = body.height * 40 / 100;
-            let [main, _side] =
-                Layout::vertical([Constraint::Fill(1), Constraint::Length(panel_height)])
-                    .areas(body);
-            main
-        }
+fn panel_split(body: Rect) -> (Rect, Rect) {
+    if body.width >= 120 {
+        let panel_width = body.width * 35 / 100;
+        let [main, side] =
+            Layout::horizontal([Constraint::Fill(1), Constraint::Length(panel_width)])
+                .areas(body);
+        (main, side)
     } else {
-        body
-    };
+        let panel_height = body.height * 40 / 100;
+        let [main, side] =
+            Layout::vertical([Constraint::Fill(1), Constraint::Length(panel_height)])
+                .areas(body);
+        (main, side)
+    }
+}
+
+fn handle_body_click(ctx: &mut InputContext, col: u16, row: u16, body: Rect, kind: ClickKind) {
+    use crate::state::PanelFocus;
+
+    if ctx.app.panel.visible && ctx.app.panel.side.is_some() {
+        let (main_area, side_area) = panel_split(body);
+
+        if contains(side_area, col, row) {
+            ctx.app.panel.focus = PanelFocus::Side;
+            return;
+        }
+
+        // Click on main area: defocus panel
+        if contains(main_area, col, row) {
+            if kind == ClickKind::Double {
+                ctx.dispatch(AppCommand::ClosePanel);
+            } else {
+                ctx.app.panel.focus = PanelFocus::Main;
+            }
+        }
+
+        // Fall through to page-specific handler with main_area
+        if !contains(main_area, col, row) {
+            return;
+        }
+
+        match ctx.app.page {
+            Page::Main => handle_main_click(ctx, col, row, main_area, kind),
+            Page::Patterns => handle_patterns_click(ctx, col, row, main_area, kind),
+            Page::Help => handle_help_click(ctx, col, row, main_area),
+            Page::Dict => handle_dict_click(ctx, col, row, main_area),
+            Page::Options => handle_options_click(ctx, col, row, main_area),
+            Page::Engine => handle_engine_click(ctx, col, row, main_area, kind),
+            Page::Script => handle_script_click(ctx, col, row, main_area),
+        }
+        return;
+    }
+
+    let page_area = body;
 
     if !contains(page_area, col, row) {
         return;