fix: improve Bluetooth reliability

kernel/src/Drivers/USB/Bluetooth/Bluetooth.hpp

@@ -49,7 +49,8 @@ namespace Drivers::USB::Bluetooth {
     int Scan(Hci::InquiryDevice* buf, int maxCount, uint32_t timeoutMs);
 
     // Initiate connection to a remote device by BD_ADDR
-    // Returns 0 on success (connection established), -1 on failure
+    // Returns 0 when ACL + A2DP are ready, -1 when the ACL connection failed,
+    // or -2 when ACL connected but A2DP setup did not complete.
     int Connect(const uint8_t* bdAddr, uint32_t timeoutMs = 10000);
 
     // Disconnect a device by BD_ADDR