Update readme, add potentiometer controls

src/main.cpp

@@ -106,6 +106,10 @@ struct AppState {
     // Corner radius selection
     S32             radius_sel;
 
+    // Knob demo state
+    F32             demo_knob_unsigned;
+    F32             demo_knob_signed;
+
     // Audio device selection
     S32             audio_device_sel;   // dropdown index: 0 = None, 1+ = device
     S32             audio_device_prev;  // previous selection for change detection
@@ -278,6 +282,24 @@ static void build_main_panel(AppState *app) {
                 .backgroundColor = g_theme.border
             ) {}
 
+            // Section: Knobs
+            ui_label("LblKnobs", "Knobs");
+            CLAY(CLAY_ID("KnobRow"),
+                .layout = {
+                    .sizing = { .width = CLAY_SIZING_FIT(), .height = CLAY_SIZING_FIT() },
+                    .childGap = uip(16),
+                    .layoutDirection = CLAY_LEFT_TO_RIGHT,
+                }
+            ) {
+                ui_knob("KnobVolume", "Volume", &app->demo_knob_unsigned, 100.0f, 0, 75.0f, 1);
+                ui_knob("KnobPan", "Pan", &app->demo_knob_signed, 50.0f, 1, 0.0f, 1);
+            }
+
+            CLAY(CLAY_ID("Sep6"),
+                .layout = { .sizing = { .width = CLAY_SIZING_GROW(), .height = CLAY_SIZING_FIXED(1) } },
+                .backgroundColor = g_theme.border
+            ) {}
+
             // Section: Windows & Modals
             ui_label("LblWindows", "Windows & Modals");
             CLAY(CLAY_ID("WindowBtnRow"),
@@ -876,6 +898,8 @@ int main(int argc, char **argv) {
     app.show_props        = 1;
     app.show_log          = 1;
     app.show_midi_devices = 1;
+    app.demo_knob_unsigned = 75.0f;
+    app.demo_knob_signed = 0.0f;
     app.demo_dropdown_sel = 1; // default to 48000 Hz
     app.radius_sel        = 1; // default to "Small" (4.0f)
     snprintf(app.demo_text_a, sizeof(app.demo_text_a), "My Instrument");