feat(window): support des fenêtres plugin-hébergées (backend)

Étend le port/usecases window et layout.customPluginLayout pour ouvrir et
piloter des fenêtres OS hébergeant un layout plugin, en réutilisant
contributes.layouts plutôt qu'un système de fenêtres parallèle. Câble la
commande Tauri et l'état app-tauri correspondants.

Cargo test -p domain --test window : 5/5
Cargo test -p application --test window_usecases : 7/7
Cargo test -p infrastructure --test window_state_store : 1/1
Cargo test -p app-tauri view_window_tests : 8/8

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

crates/application/src/layout/management.rs

@@ -15,7 +15,7 @@ use crate::error::AppError;
 use super::store::{
     default_tree, persist_doc, plugin_layout_tree, resolve_doc, LayoutKind, NamedLayout,
 };
-use crate::plugin::runtime_plugin_from_entry;
+use crate::plugin::ensure_runtime_plugin_layout_contribution;
 
 /// Lightweight descriptor of a named layout (no tree), for the layouts tab bar.
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -183,36 +183,15 @@ impl CreateLayout {
         &self,
         origin: &super::store::PluginLayoutOrigin,
     ) -> Result<(), AppError> {
-        let registry = self
-            .registry
-            .load_registry()
-            .await
-            .map_err(|e| AppError::Store(e.to_string()))?;
-        for entry in registry.plugins {
-            if entry.id != origin.plugin_id || !entry.lifecycle_state.is_runtime_active() {
-                continue;
-            }
-            let runtime =
-                runtime_plugin_from_entry(self.packages.as_ref(), self.validator.as_ref(), entry)
-                    .await?;
-            if runtime
-                .contributes
-                .layouts
-                .iter()
-                .any(|layout| layout.layout_type == origin.layout_type)
-            {
-                return Ok(());
-            }
-            return Err(AppError::Invalid(format!(
-                "plugin `{}` does not contribute layout `{}`",
-                origin.plugin_id.as_str(),
-                origin.layout_type.as_str()
-            )));
-        }
-        Err(AppError::Invalid(format!(
-            "plugin `{}` is not active at runtime",
-            origin.plugin_id.as_str()
-        )))
+        ensure_runtime_plugin_layout_contribution(
+            self.packages.as_ref(),
+            self.registry.as_ref(),
+            self.validator.as_ref(),
+            &origin.plugin_id,
+            &origin.layout_type,
+        )
+        .await
+        .map(|_| ())
     }
 }