Mark leaf Component subclasses as final

Mark 12 leaf classes (no subclasses) as final to enable
compiler devirtualization of virtual calls, reducing code
size and improving performance on embedded targets.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

esphome/components/api/api_server.h

@@ -36,11 +36,11 @@ struct SavedNoisePsk {
 } PACKED;  // NOLINT
 #endif
 
-class APIServer : public Component,
-                  public Controller
+class APIServer final : public Component,
+                        public Controller
 #ifdef USE_CAMERA
     ,
-                  public camera::CameraListener
+                        public camera::CameraListener
 #endif
 {
  public:

esphome/components/binary_sensor/filter.h

@@ -37,7 +37,7 @@ class TimeoutFilter : public Filter, public Component {
   TemplatableValue<uint32_t> timeout_delay_{};
 };
 
-class DelayedOnOffFilter : public Filter, public Component {
+class DelayedOnOffFilter final : public Filter, public Component {
  public:
   optional<bool> new_value(bool value) override;
 

esphome/components/gpio/binary_sensor/gpio_binary_sensor.h

@@ -39,7 +39,7 @@ class GPIOBinarySensorStore {
   Component *component_{nullptr};  // Pointer to the component for enable_loop_soon_any_context()
 };
 
-class GPIOBinarySensor : public binary_sensor::BinarySensor, public Component {
+class GPIOBinarySensor final : public binary_sensor::BinarySensor, public Component {
  public:
   // No destructor needed: ESPHome components are created at boot and live forever.
   // Interrupts are only detached on reboot when memory is cleared anyway.

esphome/components/gpio/switch/gpio_switch.h

@@ -8,7 +8,7 @@
 namespace esphome {
 namespace gpio {
 
-class GPIOSwitch : public switch_::Switch, public Component {
+class GPIOSwitch final : public switch_::Switch, public Component {
  public:
   void set_pin(GPIOPin *pin) { pin_ = pin; }
 

esphome/components/homeassistant/time/homeassistant_time.h

@@ -7,7 +7,7 @@
 namespace esphome {
 namespace homeassistant {
 
-class HomeassistantTime : public time::RealTimeClock {
+class HomeassistantTime final : public time::RealTimeClock {
  public:
   void setup() override;
   void update() override;

esphome/components/md5/md5.h

@@ -32,7 +32,7 @@
 namespace esphome {
 namespace md5 {
 
-class MD5Digest : public HashBase {
+class MD5Digest final : public HashBase {
  public:
   MD5Digest() = default;
   ~MD5Digest() override;

esphome/components/preferences/syncer.h

@@ -6,7 +6,7 @@
 namespace esphome {
 namespace preferences {
 
-class IntervalSyncer : public Component {
+class IntervalSyncer final : public Component {
  public:
   void set_write_interval(uint32_t write_interval) { this->write_interval_ = write_interval; }
   void setup() override {

esphome/components/restart/button/restart_button.h

@@ -6,7 +6,7 @@
 namespace esphome {
 namespace restart {
 
-class RestartButton : public button::Button, public Component {
+class RestartButton final : public button::Button, public Component {
  public:
   void dump_config() override;
 

esphome/components/safe_mode/button/safe_mode_button.h

@@ -7,7 +7,7 @@
 namespace esphome {
 namespace safe_mode {
 
-class SafeModeButton : public button::Button, public Component {
+class SafeModeButton final : public button::Button, public Component {
  public:
   void dump_config() override;
   void set_safe_mode(SafeModeComponent *safe_mode_component);

esphome/components/sha256/sha256.h

@@ -48,7 +48,7 @@ namespace esphome::sha256 {
 ///   hasher.init();
 ///   hasher.add(data, len);
 ///   hasher.calculate();
-class SHA256 : public esphome::HashBase {
+class SHA256 final : public esphome::HashBase {
  public:
   SHA256() = default;
   ~SHA256() override;

esphome/components/version/version_text_sensor.h

@@ -5,7 +5,7 @@
 
 namespace esphome::version {
 
-class VersionTextSensor : public text_sensor::TextSensor, public Component {
+class VersionTextSensor final : public text_sensor::TextSensor, public Component {
  public:
   void set_hide_hash(bool hide_hash);
   void set_hide_timestamp(bool hide_timestamp);

esphome/components/wifi/wifi_component.h

@@ -399,7 +399,7 @@ class WiFiPowerSaveListener {
 };
 
 /// This component is responsible for managing the ESP WiFi interface.
-class WiFiComponent : public Component {
+class WiFiComponent final : public Component {
  public:
   /// Construct a WiFiComponent.
   WiFiComponent();