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/web/handlers/terminal.rs

@@ -18,6 +18,7 @@ use crate::terminal::types::TerminalInfo;
 pub struct TerminalSpawnParams {
     pub working_dir: String,
     pub initial_command: Option<String>,
+    pub terminal_id: Option<String>,
 }
 
 #[derive(Deserialize)]
@@ -50,7 +51,10 @@ pub async fn terminal_spawn(
     Json(params): Json<TerminalSpawnParams>,
 ) -> Result<Json<String>, AppCommandError> {
     let manager = &state.terminal_manager;
-    let terminal_id = uuid::Uuid::new_v4().to_string();
+    let terminal_id = params
+        .terminal_id
+        .filter(|id| !id.is_empty() && id.len() <= 256)
+        .unwrap_or_else(|| uuid::Uuid::new_v4().to_string());
 
     let extra_env = prepare_credential_env(&state.data_dir);