update review tab UX/introduce shift+mousewheel for scrolling

src/tui.zig

@@ -593,11 +593,27 @@ pub const App = struct {
 
         switch (mouse.button) {
             .wheel_up => {
-                self.wheelBy(-3);
+                // shift+wheel scrolls the viewport (look-around,
+                // no cursor change). Plain wheel routes through
+                // `wheelBy` which prefers the active tab's
+                // `onCursorMove`/`onWheelMove`. We pick shift
+                // (not ctrl) because ctrl+wheel is the
+                // near-universal "zoom" gesture in browsers and
+                // editors — bending that to "scroll" would
+                // confuse muscle memory.
+                if (mouse.mods.shift) {
+                    self.scrollViewportBy(-3);
+                } else {
+                    self.wheelBy(-3);
+                }
                 return ctx.consumeAndRedraw();
             },
             .wheel_down => {
-                self.wheelBy(3);
+                if (mouse.mods.shift) {
+                    self.scrollViewportBy(3);
+                } else {
+                    self.wheelBy(3);
+                }
                 return ctx.consumeAndRedraw();
             },
             .left => {

src/tui/portfolio_tab.zig

@@ -456,16 +456,10 @@ pub const tab = struct {
         return true;
     }
 
-    /// Mouse wheel: always scroll the viewport, never move the
-    /// cursor. Keeps wheel-as-look-around and cursor-as-pointer
-    /// distinct. The framework falls through to viewport scroll
-    /// when this returns false.
-    pub fn onWheelMove(state: *State, app: *App, delta: isize) bool {
-        _ = state;
-        _ = app;
-        _ = delta;
-        return false;
-    }
+    // No `onWheelMove`: by omitting it, wheel events fall through
+    // to the framework's `onCursorMove` path. Wheel moves the
+    // cursor like j/k. PageUp / PageDown / Home / End scroll the
+    // viewport.
 
     /// Pre-empt key handler. Called by the framework BEFORE
     /// global keymap matching runs. When portfolio is in a