Migrate to Waveshare ESP32-S3-Touch-AMOLED-2.16 with auto-rotation, splash, and battery

Full hardware swap from Panlee SC01 Plus (480×320 IPS) to Waveshare 2.16"
square AMOLED (480×480, CO5300 + CST9220 + AXP2101 + QMI8658). Library
stack moves to Arduino_GFX, SensorLib, XPowersLib on the pioarduino
platform 55.03.38-1 (Arduino Core 3.x).

UI:
- 4 screens (splash, usage, controller, bluetooth) with 3-button physical
  navigation: GPIO 0 = prev, AXP PKEY = cycle, GPIO 18 = next.
- IMU-driven 90° auto-rotation. CO5300 can't rotate via MADCTL, so flush
  callback does CPU strip-rotation in PARTIAL render mode. Rotation
  transitions use AMOLED brightness flash (instant black → redraw → ramp).
- Battery indicator (Lucide icons) in upper-right, RGB565A8 alpha so it
  blends over the splash animations.
- USB plugged/unplugged auto-switches between Usage and Controller
  screens (suppressed while on splash).
- Fonts and icons re-scaled ~1.9× for the higher-DPI panel; 20px margins
  to clear rounded corners.

Splash:
- 13 × 20×20 pixel-art creature animations sourced from
  claudepix.vercel.app via tools/scrape_claudepix.js (scraper handles
  both PRESET creature-engine and standalone FRAMES+PAL formats).
  tools/convert_to_c.js emits firmware/src/splash_animations.h.
  Attribution preserved in README and the generated header.

Tooling:
- tools/png_to_lvgl.js converts alpha PNGs to LVGL RGB565A8 (planar
  layout, with --tint to colorize Lucide black-on-transparent sources).
- tools/scrape_claudepix.js, tools/convert_to_c.js for the splash
  pipeline.

Docs:
- New worktree CLAUDE.md with hardware pin map, file inventory, build
  commands, and the 8 critical gotchas (CO5300 rotation, OPI PSRAM,
  pioarduino requirement, LVGL 9 font patching, centralized touch read,
  even-aligned flush regions, touch swap/mirror values, RGB565A8 layout).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

firmware/src/power.cpp

@@ -0,0 +1,99 @@
+#include "power.h"
+#include "display_cfg.h"
+#include <Arduino.h>
+
+// Poll intervals
+#define BATTERY_POLL_MS   2000
+#define VBUS_POLL_MS      500
+
+static int      cached_pct      = -1;
+static bool     cached_charging = false;
+static bool     cached_usb      = false;
+static bool     usb_changed_flag = false;
+static bool     pwr_pressed_flag = false;
+static uint32_t last_battery_ms  = 0;
+static uint32_t last_vbus_ms     = 0;
+static uint32_t last_pwr_ms      = 0;
+#define PWR_POLL_MS 50
+
+void power_init(void) {
+    if (!pmu.begin(Wire, AXP2101_ADDR, IIC_SDA, IIC_SCL)) {
+        Serial.println("AXP2101 init failed");
+        return;
+    }
+    Serial.println("AXP2101 init OK");
+
+    // Enable battery and VBUS ADC measurements
+    pmu.enableBattDetection();
+    pmu.enableVbusVoltageMeasure();
+    pmu.enableBattVoltageMeasure();
+
+    // Enable PWR button short-press IRQ (mid button for cycling screens)
+    pmu.disableIRQ(XPOWERS_AXP2101_ALL_IRQ);
+    pmu.clearIrqStatus();
+    pmu.enableIRQ(XPOWERS_AXP2101_PKEY_SHORT_IRQ);
+
+    // Read initial state
+    cached_usb = pmu.isVbusIn();
+    cached_charging = pmu.isCharging();
+    cached_pct = pmu.getBatteryPercent();
+}
+
+void power_tick(void) {
+    uint32_t now = millis();
+
+    // Poll VBUS status
+    if (now - last_vbus_ms >= VBUS_POLL_MS) {
+        last_vbus_ms = now;
+        bool usb_now = pmu.isVbusIn();
+        if (usb_now != cached_usb) {
+            cached_usb = usb_now;
+            usb_changed_flag = true;
+        }
+        cached_charging = pmu.isCharging();
+    }
+
+    // Poll battery level
+    if (now - last_battery_ms >= BATTERY_POLL_MS) {
+        last_battery_ms = now;
+        cached_pct = pmu.getBatteryPercent();
+    }
+
+    // Poll PWR button (AXP2101 short-press IRQ)
+    if (now - last_pwr_ms >= PWR_POLL_MS) {
+        last_pwr_ms = now;
+        pmu.getIrqStatus();
+        if (pmu.isPekeyShortPressIrq()) {
+            pwr_pressed_flag = true;
+        }
+        pmu.clearIrqStatus();
+    }
+}
+
+int power_battery_pct(void) {
+    return cached_pct;
+}
+
+bool power_is_charging(void) {
+    return cached_charging;
+}
+
+bool power_is_usb_connected(void) {
+    return cached_usb;
+}
+
+bool power_usb_changed(void) {
+    if (usb_changed_flag) {
+        usb_changed_flag = false;
+        return true;
+    }
+    return false;
+}
+
+bool power_pwr_pressed(void) {
+    if (pwr_pressed_flag) {
+        pwr_pressed_flag = false;
+        return true;
+    }
+    return false;
+}