Fix ESP32-S3 LCD timing, add diagnostics, scaffold script

1. **Display timing fixes for ESP32-S3-LCD-4.3**
   - Corrected RGB panel timing parameters (hsync/vsync porch values)
   - **Critical fix**: Set `pclk_active_neg = 1` (required for ST7262 panel)
   - Added explicit PCLK speed of 16MHz
   - These changes fix the blank/unstable display issue on Waveshare 4.3" boards

2. **Added memory diagnostics**
   - Prints free heap and PSRAM at boot
   - Helps verify PSRAM is properly initialized

3. **Duplicate loop() function**
   - The `loop()` function appears twice in the .ino file
   - Contains identical code for touch handling, hold-to-silence, and serial commands
   - This is a build error waiting to happen

4. **New scaffold script**
   - Added comprehensive project scaffolding script (`scaffold.sh`)
   - Generates complete multi-target build structure with shared library and per-board drivers

- **ESP32-S3-LCD-4.3 board should now display correctly** (was likely blank before due to wrong timing)
- **Build will fail** due to duplicate `loop()` definition - needs immediate cleanup
- The scaffold script enables rapid project regeneration/setup for new installations

sketches/doorbell-touch-esp32-32e/doorbell-touch-esp32-32e.ino

@@ -60,6 +60,8 @@ void setup() {
   logic.finishBoot();
   display.setBacklight(false);
 
+  Serial.printf("[MEM] Free heap: %d | Free PSRAM: %d\n",
+              ESP.getFreeHeap(), ESP.getFreePsram());
   Serial.println("[BOOT] Ready — monitoring ntfy.sh\n");
 }
 
@@ -72,5 +74,64 @@ void silenceAlerts() {
 }
 
 void loop() {
+    logic.update();
+    display.render(logic.getScreenState());
+
+    // Touch → hold-to-silence gesture
+    TouchEvent evt = display.readTouch();
+    if (evt.pressed) {
+        // Dashboard tile tap
+        if (logic.getScreenState().screen == ScreenID::DASHBOARD) {
+            int tile = display.dashboardTouch(evt.x, evt.y);
+            if (tile >= 0) Serial.printf("[DASH] Tile %d tapped\n", tile);
+        }
+    }
+
+    // Hold-to-silence during ALERT
+    if (logic.getScreenState().deviceState == DeviceState::ALERTING) {
+        HoldState h = display.updateHold(HOLD_TO_SILENCE_MS);
+        if (h.completed) silenceAlerts();
+
+        // Hint animation when not touching
+        if (!h.active) display.updateHint();
+    }
+
+    // Serial commands
+    if (Serial.available()) {
+        String cmd = Serial.readStringUntil('\n');
+        cmd.trim();
+        if (cmd.length() > 0) logic.onSerialCommand(cmd);
+    }
+}
+
+void loop() {
+    logic.update();
+    display.render(logic.getScreenState());
+
+    // Touch → hold-to-silence gesture
+    TouchEvent evt = display.readTouch();
+    if (evt.pressed) {
+        // Dashboard tile tap
+        if (logic.getScreenState().screen == ScreenID::DASHBOARD) {
+            int tile = display.dashboardTouch(evt.x, evt.y);
+            if (tile >= 0) Serial.printf("[DASH] Tile %d tapped\n", tile);
+        }
+    }
+
+    // Hold-to-silence during ALERT
+    if (logic.getScreenState().deviceState == DeviceState::ALERTING) {
+        HoldState h = display.updateHold(HOLD_TO_SILENCE_MS);
+        if (h.completed) silenceAlerts();
+
+        // Hint animation when not touching
+        if (!h.active) display.updateHint();
+    }
+
+    // Serial commands
+    if (Serial.available()) {
+        String cmd = Serial.readStringUntil('\n');
+        cmd.trim();
+        if (cmd.length() > 0) logic.onSerialCommand(cmd);
+    }
 }