chore: import upstream snapshot with attribution

doc/devdocs/modules/interface.md

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+# Interface definition
+
+```cpp
+class PowertoyModuleIface {
+public:
+  virtual const wchar_t* get_name() = 0;
+  virtual const wchar_t** get_events() = 0;
+  virtual bool get_config(wchar_t* buffer, int *buffer_size) = 0;
+  virtual void set_config(const wchar_t* config) = 0;
+  virtual void call_custom_action(const wchar_t* action) {};
+  virtual void enable() = 0;
+  virtual void disable() = 0;
+  virtual bool is_enabled() = 0;
+  virtual void destroy() = 0;
+};
+
+typedef PowertoyModuleIface* (__cdecl *powertoy_create_func)();
+```
+
+# Runtime logic
+
+The PowerToys runner will, for each PowerToy DLL:
+  - load the DLL,
+  - call [`powertoy_create()`](#powertoy_create_func) to create the PowerToy.
+
+On the received object, the runner will call:
+  - [`get_name()`](#get_name) to get the name of the PowerToy,
+  - [`enable()`](#enable) to initialize the PowerToy.
+
+While running, the runner might call the following methods between create_powertoy()
+and destroy():
+  - [`disable()`](#disable)/[`enable()`](#enable)/[`is_enabled()`](#is_enabled) to change or get the PowerToy's enabled state,
+  - [`get_config()`](#get_config) to get the available configuration settings,
+  - [`set_config()`](#set_config) to set settings after they have been edited in the Settings editor,
+  - [`call_custom_action()`](#call_custom_action) when the user selects a custom action in the Settings editor,
+
+When terminating, the runner will:
+  - call [`disable()`](#disable),
+  - call [`destroy()`](#destroy) which should free all the memory and delete the PowerToy object,
+  - unload the DLL.
+
+
+# Method definition
+
+This section contains a more detailed description of each of the interface methods.
+
+## powertoy_create_func
+
+```cpp
+typedef PowertoyModuleIface* (__cdecl *powertoy_create_func)()
+```
+
+Typedef of the factory function that creates the PowerToy object.
+Must be exported by the DLL as `powertoy_create()`.
+
+Called by the PowerToys runner to initialize each PowerToy.
+It will be called only once before a call to [`destroy()`](#destroy) is made.
+
+The returned PowerToy should be in the disabled state. The runner will call the [`enable()`](#enable) method to start the PowerToy.
+
+In case of errors returns `nullptr`.
+
+## get_name
+
+```cpp
+virtual const wchar_t* get_name()
+```
+
+Returns the name of the PowerToy, it will be cached by the runner.
+
+## get_config
+
+```
+virtual bool get_config(wchar_t* buffer, int *buffer_size)
+```
+
+Fills a buffer with the available configuration settings.
+
+If `buffer` is a null pointer or the buffer size is not large enough sets the required buffer size in 'buffer_size' and return false.
+
+Returns true if successful.
+
+## set_config
+
+```cpp
+virtual void set_config(const wchar_t* config)
+```
+
+After the user has changed the module settings in the Settings editor, the runner calls this method to pass the updated values to the module. It's a good place to save the settings as well.
+
+## call_custom_action
+
+```cpp
+  virtual void call_custom_action(const wchar_t* action)
+```
+
+Calls a custom action in response to the user pressing the custom action button in the Settings editor.
+This can be used to spawn custom editors defined by the PowerToy.
+
+## enable
+
+```cpp
+  virtual void enable()
+```
+
+Enables the PowerToy.
+
+## disable
+
+```cpp
+  virtual void disable()
+```
+
+Disables the PowerToy, should free as much memory as possible.
+
+## is_enabled
+
+```cpp
+  virtual bool is_enabled() = 0;
+```
+
+Returns the PowerToy state.
+
+## destroy
+
+```cpp
+  virtual void destroy()
+```
+Destroy the PowerToy and free all memory.
+
+# Code organization
+
+### [`powertoy_module_interface.h`](/src/modules/interface/powertoy_module_interface.h)
+Contains the PowerToys interface definition.