Tier 2: WiFi + Bluetooth ELM327 transports

- obdcore/transport.py: pluggable byte transports -- SerialTransport,
  TcpTransport (WiFi ELM327, stdlib socket), BleTransport (experimental, via
  optional 'bleak'; background asyncio loop buffering notifications). ble_scan().
- ElmLink refactored onto a transport with .serial()/.tcp()/.ble() factories
  (close/cmd now go through self.io); no behavior change for serial.
- Controller.connect(conn={kind:serial|wifi|ble,...}); GUI connection bar gains
  a transport selector (Serial/USB/BT-SPP | WiFi host:port | Bluetooth LE + Scan).
- Classic-Bluetooth needs no new code (pairs as a serial port); WiFi needs no
  extra deps; BLE is opt-in (bleak not bundled, so CI binaries keep building).
- tests/test_transport.py: drives ElmLink over a fake ELM TCP server end-to-end
  (connect, RPM, readiness, VIN). All suites pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016yT89n4zR4qbrySoSiEyZs

gui/controller.py

@@ -55,12 +55,21 @@ class Controller:
         self.reg = PidRegistry(self.profile)
         self.dtcdb = DtcDatabase(self.profile)
 
-    def connect(self, port=None, baud=38400, mock=False):
+    def connect(self, port=None, baud=38400, mock=False, conn=None):
+        """conn: optional {'kind': 'serial'|'wifi'|'ble', ...}. Falls back to
+        serial(port, baud) for backward compatibility."""
         if mock:
             self.link = MockLink(clock=time.time)
         else:
             from obdcore.link import ElmLink            # imported lazily (needs pyserial)
-            self.link = ElmLink(port, baud)
+            c = conn or {"kind": "serial", "port": port, "baud": baud}
+            kind = c.get("kind", "serial")
+            if kind == "wifi":
+                self.link = ElmLink.tcp(c["host"], c.get("port", 35000))
+            elif kind == "ble":
+                self.link = ElmLink.ble(c["address"])
+            else:
+                self.link = ElmLink.serial(c.get("port", port), c.get("baud", baud))
             self.link.init()
         ok = self.link.connect()
         try: