fix(bluetooth): fix locate button not switching to bt_locate mode

Remove the split fast-path in doLocateHandoff that called BtLocate.handoff()
directly when the module was already loaded. That path relied on handoff()
internally calling switchMode, causing a double switchMode in the lazy-load
path and no guaranteed mode switch in the fast path.

Now doLocateHandoff always calls switchMode('bt_locate') first (lazy-loading
script/styles as needed), then calls BtLocate.handoff() in .then(). Removed
the redundant switchMode call from BtLocate.handoff() since the caller owns
the mode transition.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

static/js/modes/bluetooth.js

@@ -1790,14 +1790,8 @@ const BluetoothMode = (function() {
             mac_cluster_count: device.mac_cluster_count || 0
         };
 
-        // If BtLocate is already loaded, hand off directly
+        // Always switch to bt_locate mode first (loads script + styles if needed,
-        if (typeof BtLocate !== 'undefined') {
+        // initializes the module), then hand off device data.
-            BtLocate.handoff(payload);
-            return;
-        }
-
-        // Switch to bt_locate mode first — this loads the script, styles,
-        // and initializes the module. Then hand off the device data.
         if (typeof switchMode === 'function') {
             switchMode('bt_locate').then(function() {
                 if (typeof BtLocate !== 'undefined') {

static/js/modes/bt_locate.js

@@ -1792,11 +1792,6 @@ const BtLocate = (function() {
             const irkInput = document.getElementById('btLocateIrk');
             if (irkInput) irkInput.value = deviceInfo.irk_hex;
         }
-
-        // Switch to bt_locate mode
-        if (typeof switchMode === 'function') {
-            switchMode('bt_locate');
-        }
     }
 
     function clearHandoff() {