feat(manifest): un plugin peut contribuer des commandes slash via callback — #165 (QA verte)

Étend le manifeste et la validation SDK : un plugin déclare des commandes
slash (contributes.slashCommands) adossées à une callback (command id
enregistré via ctx.commands.registerCommand). Métadonnées UI exposées :
name, shortDescription, requiresConfirmation, when. Exemple hello-plugin
mis à jour avec une commande /hello.

Ces commandes transitent ensuite par le registry/contrat unifié (#162).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/commands-and-feedback.md

@@ -5,14 +5,20 @@ background work.
 
 ## Contract
 
-Every human menu click follows this sequence:
+Every menu click or plugin slash command follows this sequence:
 
 ```text
-menu item -> command id -> registered command handler -> optional task -> feedback surfaces
+manifest contribution -> command id -> registered command handler -> optional task -> feedback surfaces
 ```
 
 - A manifest menu item declares a `command` id; it does not run tools directly.
+- A manifest slash command declares a slash `name`, autocomplete metadata and a
+  `command` id; it does not run tools directly.
+- Menu items and slash commands may share the same `command` id, or point to
+  different handlers. The plugin owns that choice.
 - The command handler is the only place that decides whether work should start.
+- The host slash-command registry only lists/filters metadata and returns a
+  callback dispatch effect. The plugin handler decides what the command does.
 - A launched process is represented by a background task returned from
   `ctx.services.tasks.runCommand()`.
 - A skipped command is represented by the command handler return value and logs,

examples/hello-plugin/idea-plugin.json

@@ -32,6 +32,14 @@
         "order": 10
       }
     ],
+    "slashCommands": [
+      {
+        "name": "/hello",
+        "shortDescription": "Run the hello-plugin callback",
+        "command": "hello-plugin",
+        "requiresConfirmation": false
+      }
+    ],
     "layouts": [
       {
         "type": "hello-plugin.hello-world",

src/manifest.ts

@@ -16,6 +16,7 @@ export interface IdeAPluginManifest {
   contributes?: {
     menus?: IdeAPluginTopLevelMenuContribution[];
     menuItems?: IdeAPluginMenuItemContribution[];
+    slashCommands?: IdeAPluginSlashCommandContribution[];
     layouts?: IdeAPluginLayoutContribution[];
     mcpServers?: IdeAPluginMcpServerContribution[];
   };
@@ -47,6 +48,19 @@ export interface IdeAPluginMenuItemContribution {
   when?: string;
 }
 
+export interface IdeAPluginSlashCommandContribution {
+  /** Slash name shown in autocomplete. Must start with "/". */
+  name: string;
+  /** Short autocomplete/help description. */
+  shortDescription: string;
+  /** Command callback id registered through ctx.commands.registerCommand(). */
+  command: string;
+  /** Ask for host confirmation before dispatching the callback. */
+  requiresConfirmation?: boolean;
+  /** Reserved declarative condition for host-side availability. */
+  when?: string;
+}
+
 export interface IdeAPluginLayoutContribution {
   type: string;
   label: string;
@@ -196,6 +210,16 @@ function validateContributes(value: unknown, errors: string[]): void {
     optionalString(item, "icon", errors, `contributes.menuItems[${index}].icon`);
     optionalString(item, "when", errors, `contributes.menuItems[${index}].when`);
   });
+  validateArray(value, "slashCommands", errors, (command, index) => {
+    requireString(command, "name", errors, `contributes.slashCommands[${index}].name`);
+    requireString(command, "shortDescription", errors, `contributes.slashCommands[${index}].shortDescription`);
+    requireString(command, "command", errors, `contributes.slashCommands[${index}].command`);
+    if (typeof command.name === "string" && !command.name.startsWith("/")) {
+      errors.push(`contributes.slashCommands[${index}].name must start with "/"`);
+    }
+    optionalBoolean(command, "requiresConfirmation", errors, `contributes.slashCommands[${index}].requiresConfirmation`);
+    optionalString(command, "when", errors, `contributes.slashCommands[${index}].when`);
+  });
   validateArray(value, "layouts", errors, (layout, index) => {
     requireString(layout, "type", errors, `contributes.layouts[${index}].type`);
     requireString(layout, "label", errors, `contributes.layouts[${index}].label`);