fix(windows): restauration panel-only des fenêtres détachées suivant le projet en focus (#47)

Partie backend. Les fenêtres/panneaux détachés étaient restaurés avec un
project_id figé au moment du détachement, si bien qu'ils restaient collés à
un projet mort ou incohérent après redémarrage. Ils sont désormais restaurés
en mode panel-only, sans project_id figé, et suivent le projet en focus de la
fenêtre principale via un event focused-project exposé par la couche fenêtre.

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

crates/app-tauri/src/state.rs

@@ -62,6 +62,7 @@ use domain::{
     InboxError, InboxItem, InboxItemKind, InboxReceiptStatus, InboxSource, Project, ProjectId,
     TaskId, TicketId,
 };
+use serde::{Deserialize, Serialize};
 use serde_json::{json, Map, Value};
 use uuid::Uuid;
 
@@ -89,6 +90,18 @@ use crate::openai_tools::{AppOpenAiToolInvoker, LateBoundOpenAiToolInvoker};
 use crate::pty::PtyBridge;
 use crate::tickets::AppTicketToolProvider;
 
+/// Focused project snapshot shared with detached panel windows.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct FocusedProjectDto {
+    /// Project id as a string.
+    pub id: String,
+    /// Project display name.
+    pub name: String,
+    /// Absolute project root.
+    pub root: String,
+}
+
 use infrastructure::StdioTransport;
 
 use interprocess::local_socket::tokio::Listener as LocalSocketListener;
@@ -907,6 +920,8 @@ pub struct AppState {
     pub snapshot_open_windows: Arc<SnapshotOpenWindows>,
     /// Load restorable Tauri webview-window state on startup.
     pub restore_open_windows: Arc<RestoreOpenWindows>,
+    /// Project currently focused by the main window; panel-only windows follow it.
+    focused_project: Mutex<Option<FocusedProjectDto>>,
     // --- Background tasks (B8) ---
     /// Spawn a command-backed first-class background task.
     pub spawn_background_command: Arc<SpawnBackgroundCommand>,
@@ -2376,6 +2391,7 @@ impl AppState {
             move_tab,
             snapshot_open_windows,
             restore_open_windows,
+            focused_project: Mutex::new(None),
             spawn_background_command,
             cancel_background_task,
             retry_background_task,
@@ -2383,6 +2399,23 @@ impl AppState {
         }
     }
 
+    /// Updates the focused project state. `None` means no project is focused/open.
+    pub fn set_focused_project(&self, project: Option<FocusedProjectDto>) {
+        *self
+            .focused_project
+            .lock()
+            .expect("focused project mutex poisoned") = project;
+    }
+
+    /// Returns the current focused project, if any.
+    #[must_use]
+    pub fn get_focused_project(&self) -> Option<FocusedProjectDto> {
+        self.focused_project
+            .lock()
+            .expect("focused project mutex poisoned")
+            .clone()
+    }
+
     /// Starts a [`FsOrchestratorWatcher`] for `project` if one is not already
     /// running for it (idempotent). The watcher tails the project's
     /// `.ideai/requests/` tree and dispatches each request through the shared