Add simple STHS34PF80 demo sketch

- Clean, minimal example showing basic sensor usage
- Always displays ambient temperature in Celsius
- Only shows detection values when events occur (presence, motion, temp shock)
- Only displays object temperatures when presence or motion detected
- 100ms update rate for responsive monitoring

🤖 Generated with [Claude Code](https://claude.ai/code)

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

examples/sths34pf80_simple/sths34pf80_simple.ino

@@ -0,0 +1,62 @@
+// Basic test for STHS34PF80 infrared sensor
+
+#include "Adafruit_STHS34PF80.h"
+
+Adafruit_STHS34PF80 sths;
+
+void setup() {
+  Serial.begin(115200);
+  while (!Serial) delay(10);
+
+  Serial.println("Adafruit STHS34PF80 test!");
+
+  if (!sths.begin()) {
+    Serial.println("Could not find a valid STHS34PF80 sensor, check wiring!");
+    while (1) delay(10);
+  }
+
+  Serial.println("STHS34PF80 Found!");
+}
+
+void loop() {
+  if (!sths.isDataReady()) {
+    delay(10);
+    return;
+  }
+  
+  Serial.print("Data ready! ");
+  
+  // Read temperature data
+  Serial.print("Amb: ");
+  Serial.print(sths.readAmbientTemperature(), 2);
+  Serial.print("°C");
+  
+  // Check for presence and show data if detected
+  if (sths.isPresence()) {
+    Serial.print(" PRESENCE: ");
+    Serial.print(sths.readPresence());
+  }
+  
+  // Check for motion and show data if detected
+  if (sths.isMotion()) {
+    Serial.print(" MOTION: ");
+    Serial.print(sths.readMotion());
+  }
+  
+  // Check for temperature shock and show data if detected
+  if (sths.isTempShock()) {
+    Serial.print(" TEMP_SHOCK: ");
+    Serial.print(sths.readTempShock());
+  }
+  
+  // Show object temperatures only if presence or motion detected
+  if (sths.isPresence() || sths.isMotion()) {
+    Serial.print(" Obj: ");
+    Serial.print(sths.readObjectTemperature());
+    Serial.print(", Comp: ");
+    Serial.print(sths.readCompensatedObjectTemperature());
+  }
+  
+  Serial.println();
+  delay(100);
+}