chore(tauri): don't auto-open devtools on launch

Removes the #[cfg(debug_assertions)] open_devtools() block from setup().
DevTools remain available in dev builds via the standard WebKit shortcut
(Ctrl+Shift+I) and right-click → Inspect, but no longer pop up automatically
on every dev launch. Less visual clutter when iterating without needing the
inspector.

Production behaviour is unchanged — devtools stay hard-stripped from
release builds via Tauri's default `windows[].devtools=false` for release.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src-tauri/src/lib.rs

@@ -3621,14 +3621,6 @@ pub fn run() {
                 }
             }
 
-            #[cfg(debug_assertions)]
-            {
-                use tauri::Manager;
-                if let Some(win) = app.get_webview_window("main") {
-                    win.open_devtools();
-                }
-            }
-
             // ── System tray ───────────────────────────────────────────────
             // Always build on startup when possible; the frontend calls toggle_tray_icon(false)
             // immediately after load if the user has disabled the tray icon.