[esp32] Stub arduino-esp32 with INTERFACE re-export to framework (#16695)

esphome/components/esp32/__init__.py

@@ -2583,6 +2583,26 @@ def _write_idf_component_yml():
                 "override_path": str(stub_path),
             }
 
+        # On the PlatformIO toolchain, framework-arduinoespressif32 already
+        # ships arduino-esp32. Stub the managed component so anything that
+        # `REQUIRES arduino-esp32` (e.g. third-party FastLED) resolves to a
+        # CMake target that re-exports the framework's INTERFACE properties
+        # (INCLUDE_DIRS, public compile options like -DESP32, transitive
+        # REQUIRES) instead of triggering a duplicate download/rebuild.
+        if CORE.using_toolchain_platformio:
+            arduino_stub = stubs_dir / "arduino-esp32"
+            arduino_stub.mkdir(exist_ok=True)
+            write_file_if_changed(
+                arduino_stub / "CMakeLists.txt",
+                "idf_component_register()\n"
+                "target_link_libraries(${COMPONENT_LIB} "
+                f"INTERFACE idf::{ARDUINO_FRAMEWORK_NAME})\n",
+            )
+            dependencies[ARDUINO_ESP32_COMPONENT_NAME] = {
+                "version": "*",
+                "override_path": str(arduino_stub),
+            }
+
         # Remove stubs for components that are now required by enabled libraries
         for component_name in required_idf_components:
             stub_path = stubs_dir / _idf_component_stub_name(component_name)