optimize: terminal spawn lifecycle to eliminate output race condition

Move PTY spawn from context layer to view layer so event subscription
happens before spawn, preventing loss of initial terminal output.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src-tauri/src/commands/terminal.rs

@@ -69,11 +69,14 @@ pub(crate) fn prepare_credential_env(
 pub async fn terminal_spawn(
     working_dir: String,
     initial_command: Option<String>,
+    terminal_id: Option<String>,
     manager: State<'_, TerminalManager>,
     app_handle: tauri::AppHandle,
     window: tauri::WebviewWindow,
 ) -> Result<String, TerminalError> {
-    let terminal_id = uuid::Uuid::new_v4().to_string();
+    let terminal_id = terminal_id
+        .filter(|id| !id.is_empty() && id.len() <= 256)
+        .unwrap_or_else(|| uuid::Uuid::new_v4().to_string());
 
     let app_data_dir = app_handle
         .path()