Remove deprecated offsetof hack from NumberTraits

NumberTraits no longer needs get_device_class_ref() or
get_unit_of_measurement_ref() — no internal callers exist.
Callers should use number->get_device_class_ref() directly.
Eliminates offsetof warning on non-standard-layout type.

esphome/components/number/number.cpp

@@ -1,5 +1,4 @@
 #include "number.h"
-#include <cstddef>
 #include "esphome/core/defines.h"
 #include "esphome/core/controller_registry.h"
 #include "esphome/core/log.h"
@@ -20,18 +19,6 @@ void log_number(const char *tag, const char *prefix, const char *type, Number *o
   LOG_ENTITY_DEVICE_CLASS(tag, prefix, *obj);
 }
 
-// Deprecated backward-compat: delegate to parent Number's EntityBase methods
-StringRef NumberTraits::get_device_class_ref() const {
-  const auto *number =
-      reinterpret_cast<const Number *>(reinterpret_cast<const uint8_t *>(this) - offsetof(Number, traits));
-  return number->get_device_class_ref();
-}
-StringRef NumberTraits::get_unit_of_measurement_ref() const {
-  const auto *number =
-      reinterpret_cast<const Number *>(reinterpret_cast<const uint8_t *>(this) - offsetof(Number, traits));
-  return number->get_unit_of_measurement_ref();
-}
-
 void Number::publish_state(float state) {
   this->set_has_state(true);
   this->state = state;

esphome/components/number/number_traits.h

@@ -1,7 +1,7 @@
 #pragma once
 
-#include "esphome/core/entity_base.h"
-#include "esphome/core/helpers.h"
+#include <cmath>
+#include <cstdint>
 
 namespace esphome::number {
 
@@ -27,16 +27,6 @@ class NumberTraits {
   void set_mode(NumberMode mode) { this->mode_ = mode; }
   NumberMode get_mode() const { return this->mode_; }
 
-  // Deprecated: use Number::get_device_class_ref() instead.
-  // Delegates to parent Number's EntityBase via offsetof.
-  ESPDEPRECATED("Use number->get_device_class_ref() instead. Removed in 2027.2.0", "2026.8.0")
-  StringRef get_device_class_ref() const;
-
-  // Deprecated: use Number::get_unit_of_measurement_ref() instead.
-  // Delegates to parent Number's EntityBase via offsetof.
-  ESPDEPRECATED("Use number->get_unit_of_measurement_ref() instead. Removed in 2027.2.0", "2026.8.0")
-  StringRef get_unit_of_measurement_ref() const;
-
  protected:
   float min_value_ = NAN;
   float max_value_ = NAN;