feat: Add slashcommand api

docs-site/docs/plugin-development/api/commands.md

@@ -0,0 +1,114 @@
+---
+sidebar_position: 12
+---
+
+# Slash Commands API
+
+The Commands API lets plugins register `/` slash commands. When a user types `/` in the chat composer, MetoYou shows a Discord-style autocomplete menu of available commands. Selecting a command (click, `Enter`, or `Tab`) runs it — either immediately when it declares no options, or after the user types the requested arguments.
+
+## Required Capabilities
+
+| Method                            | Capability    |
+| --------------------------------- | ------------- |
+| `commands.register(id, command)`  | `ui.commands` |
+| `commands.list()`                 | `ui.commands` |
+
+Every registration returns a disposable. Push it into `context.subscriptions` so the command is removed when the plugin unloads.
+
+## Command Scope
+
+A command's `scope` controls where it appears:
+
+| Scope               | Available in                                  |
+| ------------------- | --------------------------------------------- |
+| `global` (default)  | Chat servers **and** direct messages          |
+| `server`            | Only while a chat server is the active surface |
+
+Use `global` for commands that work without a server context (e.g. `/help`, `/shrug`). Use `server` for commands that act on the current server, channel, or members.
+
+## Options and Argument Parsing
+
+Declare `options` to describe the arguments a command accepts. MetoYou parses what the user typed after the command name and passes the result to `run` as `context.args`, keyed by option name.
+
+```ts
+interface PluginApiSlashCommandOption {
+  description?: string;
+  name: string;
+  required?: boolean;
+  // 'rest' captures all remaining text; otherwise a single whitespace-delimited token
+  type?: 'string' | 'number' | 'boolean' | 'rest';
+}
+```
+
+- Positional options are filled left-to-right from whitespace-delimited tokens.
+- A `rest` option captures all remaining text verbatim (use it last, for free-form text).
+- Missing positional values are passed as empty strings.
+- The autocomplete menu shows required options as `<name>` and optional ones as `[name]`.
+
+Values arrive as strings; convert `number`/`boolean` types yourself inside `run`.
+
+## Command Context
+
+`run` receives a context that extends the standard action context (`source: 'slashCommand'`) with the invocation details:
+
+```ts
+interface PluginApiSlashCommandContext extends PluginApiActionContext {
+  args: Record<string, string>; // parsed values keyed by option name
+  command: string;              // invoked name without the leading slash
+  rawArgs: string;              // raw text typed after the command name
+  // inherited: server, textChannel, voiceChannel, user, source
+}
+```
+
+## Register a Command
+
+```js
+export function activate(context) {
+  const api = context.api;
+
+  // Server-scoped command with a free-form message argument.
+  context.subscriptions.push(
+    api.commands.register('announce', {
+      name: 'announce',
+      description: 'Post an announcement to the current channel',
+      icon: '📢',
+      scope: 'server',
+      options: [{ name: 'message', type: 'rest', required: true }],
+      run: (slash) => {
+        api.messages.send(`📢 ${slash.args.message}`, slash.textChannel?.id);
+      }
+    })
+  );
+
+  // Global command that works in servers and DMs.
+  context.subscriptions.push(
+    api.commands.register('shrug', {
+      name: 'shrug',
+      description: 'Append the shrug emoticon',
+      scope: 'global',
+      run: () => api.messages.send('¯\\_(ツ)_/¯')
+    })
+  );
+}
+```
+
+`api.messages.send` requires the `messages.send` capability, so the example above declares both `ui.commands` and `messages.send` in its manifest.
+
+## List Registered Commands
+
+```js
+const allCommands = context.api.commands.list();
+```
+
+Returns every slash command currently registered across all active plugins, including their scope and options.
+
+## Built-in Commands
+
+MetoYou ships first-party commands that are always available without any plugin, such as `/lenny` (posts `( ͡° ͜ʖ ͡°)`). They appear in the same autocomplete menu tagged as **Built-in**. Plugin commands are listed alongside them; if a plugin registers a command with the same name as a built-in, both appear and the user can pick either.
+
+## How Input Is Handled
+
+- Typing `/` opens the menu; typing more characters filters by command name (prefix matches rank first).
+- Picking a command **without options** runs it immediately and clears the composer.
+- Picking a command **with options** fills `/name ` so the user can type arguments, then `Enter` runs it.
+- Slash input is intercepted and never posted as a chat message. Text that starts with `/` but matches no registered command falls through and is sent as a normal message.

docs-site/docs/plugin-development/api/ui.md

@@ -6,6 +6,8 @@ sidebar_position: 11
 
 The UI API lets plugins add pages, settings pages, side panels, channel sections, actions, embed renderers, and controlled DOM mounts.
 
+For `/` slash commands in the chat composer, see the [Slash Commands API](./commands.md) (`api.commands`).
+
 Prefer registered UI contributions over direct DOM mounting. Contribution APIs let Angular render the plugin UI when the matching app surface exists. Direct DOM mounting runs immediately and throws if the target selector is not present.
 
 ## Required Capabilities