Add SDK RTC and IMU hardware abstraction support

Integrate SDK-based RTC and IMU backends as alternatives to direct hardware access. HalClock now attempts SDK RTC initialization and caches time values for reliability. HalTiltSensor adds SDK IMU backend with fallback logic. ClockOffsetActivity gains touch and swipe gesture support for field navigation.

lib/hal/HalTiltSensor.cpp

@@ -26,6 +26,15 @@ bool HalTiltSensor::readReg(uint8_t reg, uint8_t* val) const {
 }
 
 bool HalTiltSensor::readGyro(float& gx, float& gy, float& gz) const {
+  if (_backend == Backend::SdkImu) {
+    Imu::Sample sample;
+    if (!_sdkImu.read(sample)) return false;
+    gx = sample.gx;
+    gy = sample.gy;
+    gz = sample.gz;
+    return true;
+  }
+
   Wire.beginTransmission(_i2cAddr);
   Wire.write(REG_GX_L);  // Start reading at Gyro X Low
   if (Wire.endTransmission(false) != 0) {
@@ -52,11 +61,22 @@ bool HalTiltSensor::readGyro(float& gx, float& gy, float& gz) const {
 }
 
 void HalTiltSensor::begin() {
+  _backend = Backend::None;
   if (!gpio.deviceIsX3()) {
-    _available = false;
+    _available = _sdkImu.begin();
+    if (!_available) {
+      LOG_ERR("GYR", "SDK IMU not found");
+      return;
+    }
+    _backend = Backend::SdkImu;
+    _initMs = millis();
+    _lastPollMs = millis();
+    LOG_INF("GYR", "SDK IMU initialized");
     return;
   }
 
+  _backend = Backend::Qmi8658;
+
   // Try primary address, then alternate
   uint8_t whoami = 0;
   _i2cAddr = I2C_ADDR_QMI8658;
@@ -89,6 +109,14 @@ bool HalTiltSensor::wake() {
     return false;
   }
 
+  if (_backend == Backend::SdkImu) {
+    _lastPollMs = millis();
+    _lastTiltMs = millis();
+    _wakeMs = millis();
+    _isAwake = true;
+    return true;
+  }
+
   // Wait for init to complete before waking
   if ((millis() - _initMs) < SLEEP_STABILIZE_MS) {
     return false;
@@ -111,6 +139,13 @@ bool HalTiltSensor::deepSleep() {
     return false;
   }
 
+  if (_backend == Backend::SdkImu) {
+    clearPendingEvents();
+    _inTilt = false;
+    _isAwake = false;
+    return true;
+  }
+
   if ((millis() - _wakeMs) < SLEEP_STABILIZE_MS) {
     return false;
   }