docs(sdk): feedback visible via windows.open + séparation Codex skills documentées — commands-and-feedback (surface normative + exemple), layouts-react (type↔contributes.layouts, capacité ui), manifest (exemple complet menu+layout+ui), windows (contrat ui, retour structuré), packaging-distribution (idea_plugin_install_from_directory, sémantique plugin_reloaded/ESM), nouveau codex-skills-and-idea-plugins, README (lien) — #280 QA verte

docs/commands-and-feedback.md

@@ -26,8 +26,9 @@ manifest contribution -> command id -> registered command handler -> optional ta
 - Feedback objects must be stable enough for agents and programmatic callers to
   parse, and their messages must be readable by humans.
 - The current human menu-click UI does not guarantee display of a command
-  handler return value. Use logs, Work/task state or plugin-owned UI/files when
-  a human needs visible feedback today.
+  handler return value. When a human must see feedback from a menu action, open
+  or focus a plugin layout/window from the handler with
+  `ctx.services.windows.open({ layoutType, state })`.
 
 ## Preconditions
 
@@ -76,6 +77,9 @@ Visible surfaces are intentionally distinct:
 - Command return value: immediate feedback for programmatic callers, agents and
   future host surfaces. It is not a guaranteed visible UI surface for current
   human menu clicks.
+- Plugin layout/window: the normative visible feedback surface for menu actions
+  that need to show status, results or next steps to a human. The layout must be
+  declared in `idea-plugin.json` and registered during activation.
 - Plugin logs: diagnostics for developers and operators.
 - Work/background-task surfaces: only for tasks actually launched through
   `runCommand()`.
@@ -105,6 +109,40 @@ state when invoked instead of assuming a watch was installed at activation.
 
 ## Example
 
+Visible menu feedback:
+
+```tsx
+import type { IdeAPluginModule, PluginLayoutProps } from "@idea/plugin-sdk";
+
+function HealthView(_props: PluginLayoutProps<{ source?: string }>) {
+  return <section>Unity tools are ready.</section>;
+}
+
+const plugin: IdeAPluginModule = {
+  activate(ctx) {
+    ctx.layouts?.register({
+      type: "unity-plugin.health",
+      component: HealthView
+    });
+
+    ctx.commands?.registerCommand("unity-plugin.health", async () => {
+      const win = await ctx.services?.windows.open({
+        layoutType: "unity-plugin.health",
+        state: { source: "menu" }
+      });
+
+      return win
+        ? { status: "opened", message: "Opened Unity Health.", alreadyOpen: win.alreadyOpen }
+        : { status: "skipped", reason: "ui-service-unavailable", message: "UI service unavailable." };
+    });
+  }
+};
+
+export default plugin;
+```
+
+Background task feedback:
+
 ```ts
 const project = await ctx.services?.workspace.getCurrentProject();
 if (!project) {