feat(menu): add Restart action between separator and Exit

One-click relaunch of the running binary via a detached cmd.exe handoff:
timeout /t 1 /nobreak >/dev/null & start "" "<exe>" — the 1s wait outlives the
parent so the relaunched instance acquires Global\ClaudeCodeUsageBubble
without ERROR_ALREADY_EXISTS.

- New IDM_RESTART (33) wired into show_context_menu + on_menu_command.
- Match arm placed above the IDM_LANG_BASE guard so future ids in the
  static band can't be swallowed by the dynamic-language catch-all.
- Settings flushed defensively before quit (clone-then-save to avoid
  blocking the UI thread on disk I/O while holding lock_state).
- Rejects current_exe paths containing '%' (same defense as
  update::install — cmd.exe expands %var% inside quotes).
- New 'restart' string in LocaleStrings + translation in all 8 locales.

src/app.rs

@@ -6,6 +6,8 @@
 // message-only window owned by this module.
 
 use std::collections::HashMap;
+use std::os::windows::process::CommandExt;
+use std::process::{Command, Stdio};
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex, MutexGuard, OnceLock};
 use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
@@ -69,6 +71,7 @@ const IDM_MODEL_CHATGPT: u16 = 21;
 const IDM_START_WITH_WINDOWS: u16 = 30;
 const IDM_RESET_POSITION: u16 = 31;
 const IDM_VERSION_ACTION: u16 = 32;
+const IDM_RESTART: u16 = 33;
 const IDM_LANG_SYSTEM: u16 = 40;
 // 50 is reserved by tray::IDM_TOGGLE_WIDGET — keep the auto-update range
 // clear of it (and any future tray ids in the 5x band).
@@ -385,8 +388,12 @@ pub fn on_menu_command(id: u32, _owner_hwnd: HWND) {
             set_update_check_interval(Some(settings::UPDATE_CHECK_WEEKLY_SECS))
         }
         IDM_LANG_SYSTEM => set_language(None),
-        x if x >= IDM_LANG_BASE => set_language_by_index((x - IDM_LANG_BASE) as usize),
+        // Static ids in the 30-99 band must match BEFORE the dynamic
+        // language guard, otherwise `x >= IDM_LANG_BASE` would swallow any
+        // future id that creeps into the >=100 range.
         tray::IDM_TOGGLE_WIDGET => toggle_widget_visibility(),
+        IDM_RESTART => restart_app(),
+        x if x >= IDM_LANG_BASE => set_language_by_index((x - IDM_LANG_BASE) as usize),
         _ => {}
     }
 }
@@ -1034,6 +1041,7 @@ fn show_context_menu(owner_hwnd: HWND) {
             if snap.widget_visible { MF_CHECKED } else { MENU_ITEM_FLAGS(0) },
         );
         let _ = AppendMenuW(menu, MF_SEPARATOR, 0, PCWSTR::null());
+        append_item(menu, IDM_RESTART, &snap.strings.restart, MENU_ITEM_FLAGS(0));
         append_item(menu, IDM_EXIT, &snap.strings.exit, MENU_ITEM_FLAGS(0));
 
         let mut pt = POINT::default();
@@ -1361,6 +1369,62 @@ fn set_update_check_interval(value: Option<u64>) {
     }
 }
 
+// ---------- Restart ----------
+
+// Windows CreateProcess flags. Match the values used by `update::install`
+// so the cmd-handoff child detaches cleanly without flashing a console.
+const RESTART_CREATE_NO_WINDOW: u32 = 0x0800_0000;
+const RESTART_DETACHED_PROCESS: u32 = 0x0000_0008;
+
+/// Relaunch the running binary via a detached cmd.exe handoff.
+///
+/// The 1-second `timeout` gives the current process time to release the
+/// `Global\ClaudeCodeUsageBubble` mutex before the relaunched instance's
+/// `CreateMutexW` runs, otherwise the new instance would see
+/// `ERROR_ALREADY_EXISTS` and exit immediately.
+fn restart_app() {
+    // Defensive flush — bubble positions and most settings already persist
+    // on change, but a final save is cheap insurance. Snapshot then drop the
+    // lock before the disk write so the UI thread doesn't block on I/O.
+    let snap = lock_state().as_ref().map(|s| s.settings.clone());
+    if let Some(s) = snap {
+        settings::save(&s);
+    }
+
+    let exe = match std::env::current_exe() {
+        Ok(p) => p,
+        Err(e) => {
+            log::error!("restart: current_exe failed: {e}");
+            return;
+        }
+    };
+    let exe_str = exe.to_string_lossy();
+    // cmd.exe expands `%var%` inside double quotes, so a path containing `%`
+    // would let the environment leak into the relaunch. Refuse — matches the
+    // defense already used in `update::install`.
+    if exe_str.contains('%') {
+        log::error!("restart: refusing path containing '%': {exe_str}");
+        return;
+    }
+    let exe_str = exe_str.replace('"', "");
+    let cmd = format!(r#"timeout /t 1 /nobreak >nul & start "" "{exe_str}""#);
+    let spawned = Command::new("cmd.exe")
+        .raw_arg("/c")
+        .raw_arg(format!("\"{cmd}\""))
+        .creation_flags(RESTART_CREATE_NO_WINDOW | RESTART_DETACHED_PROCESS)
+        .stdin(Stdio::null())
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .spawn();
+    match spawned {
+        Ok(_) => {
+            log::info!("restart: cmd handoff spawned, posting quit");
+            unsafe { PostQuitMessage(0) };
+        }
+        Err(e) => log::error!("restart: cmd spawn failed: {e}"),
+    }
+}
+
 // ---------- Start-with-Windows ----------
 
 fn is_startup_enabled() -> bool {

src/i18n/locales/de.toml

@@ -29,6 +29,7 @@ auto_check_hourly = "Stündlich"
 auto_check_daily = "Täglich"
 auto_check_weekly = "Wöchentlich"
 exit = "Beenden"
+restart = "Neu starten"
 show_widget = "Widget anzeigen"
 session_window = "5h"
 weekly_window = "7d"

src/i18n/locales/en.toml

@@ -29,6 +29,7 @@ auto_check_hourly = "Hourly"
 auto_check_daily = "Daily"
 auto_check_weekly = "Weekly"
 exit = "Exit"
+restart = "Restart"
 show_widget = "Show widget"
 session_window = "5h"
 weekly_window = "7d"

src/i18n/locales/es.toml

@@ -29,6 +29,7 @@ auto_check_hourly = "Cada hora"
 auto_check_daily = "Cada día"
 auto_check_weekly = "Cada semana"
 exit = "Salir"
+restart = "Reiniciar"
 show_widget = "Mostrar widget"
 session_window = "5h"
 weekly_window = "7d"

src/i18n/locales/fr.toml

@@ -29,6 +29,7 @@ auto_check_hourly = "Toutes les heures"
 auto_check_daily = "Quotidienne"
 auto_check_weekly = "Hebdomadaire"
 exit = "Quitter"
+restart = "Redémarrer"
 show_widget = "Afficher le widget"
 session_window = "5h"
 weekly_window = "7j"

src/i18n/locales/ja.toml

@@ -29,6 +29,7 @@ auto_check_hourly = "1時間ごと"
 auto_check_daily = "毎日"
 auto_check_weekly = "毎週"
 exit = "終了"
+restart = "再起動"
 show_widget = "ウィジェットを表示"
 session_window = "5時間"
 weekly_window = "7日"

src/i18n/locales/ko.toml

@@ -29,6 +29,7 @@ auto_check_hourly = "매시간"
 auto_check_daily = "매일"
 auto_check_weekly = "매주"
 exit = "종료"
+restart = "다시 시작"
 show_widget = "위젯 표시"
 session_window = "5시간"
 weekly_window = "7일"

src/i18n/locales/nl.toml

@@ -29,6 +29,7 @@ auto_check_hourly = "Per uur"
 auto_check_daily = "Dagelijks"
 auto_check_weekly = "Wekelijks"
 exit = "Afsluiten"
+restart = "Opnieuw starten"
 show_widget = "Widget tonen"
 session_window = "5u"
 weekly_window = "7d"

src/i18n/locales/zh-TW.toml

@@ -29,6 +29,7 @@ auto_check_hourly = "每小時"
 auto_check_daily = "每天"
 auto_check_weekly = "每週"
 exit = "結束"
+restart = "重新啟動"
 show_widget = "顯示小工具"
 session_window = "5 小時"
 weekly_window = "7 日"

src/i18n/mod.rs

@@ -49,6 +49,7 @@ pub struct LocaleStrings {
     pub auto_check_daily: String,
     pub auto_check_weekly: String,
     pub exit: String,
+    pub restart: String,
     pub show_widget: String,
     pub session_window: String,
     pub weekly_window: String,