Section 1 backend: VIN/Mode-09, readiness monitors, freeze-frame, trip/perf

obdcore additions (all standard SAE J1979, vehicle-agnostic, hardware-free
tested):
- obdservices.py: decode_vin (Mode 09), decode_readiness (Mode 01 PID 01 I-M
  monitors + MIL + DTC count, spark/diesel monitor sets), freeze-frame PID set.
- link.py: ElmLink.read_vehicle_info (VIN/cal/ECU), read_readiness, read_freeze_frame.
- trip.py: TripComputer (MAF-based MPG + trip totals) and PerformanceMeter
  (0-60 / 1/4-mile with launch detection).
- mock.py: speed/MAF/readiness + service stubs for GUI mock mode.
- tests/test_services.py: VIN, readiness bit decode, trip math, 0-60/quarter.

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

obdcore/link.py

@@ -172,6 +172,41 @@ class ElmLink:
         data = self._bytes(lines)
         return 0x44 in data or ("OK" in "".join(lines).upper())
 
+    # -- standard OBD services (Mode 09 / 01-01 / 02) --
+    def read_vehicle_info(self, timeout=2.0):
+        """Mode 09: VIN + calibration IDs + ECU name. Returns a dict."""
+        from . import obdservices as svc
+        vin = svc.decode_vin(self._bytes(self.cmd("0902", timeout=timeout)))
+        cal = svc.decode_ascii_block(self._bytes(self.cmd("0904", timeout=timeout)), 0x04)
+        ecu = svc.decode_ascii_block(self._bytes(self.cmd("090A", timeout=timeout)), 0x0A)
+        return {"vin": vin, "calibration": cal, "ecu_name": ecu}
+
+    def read_readiness(self, timeout=1.0):
+        """Mode 01 PID 01: MIL, DTC count, and I-M readiness monitors."""
+        from . import obdservices as svc
+        data = self.read_m01("01", 4, timeout=timeout)
+        return svc.decode_readiness(data) if data else None
+
+    def read_freeze_frame(self, timeout=0.6):
+        """Mode 02: the DTC that set the freeze frame + the standard PID snapshot."""
+        from . import obdservices as svc
+        out = {"dtc": None, "values": []}
+        d = self._bytes(self.cmd("0202", timeout=timeout))
+        if 0x42 in d:
+            r = d[d.index(0x42) + 2:]            # after '42 02'
+            if len(r) >= 2 and (r[0] or r[1]):
+                out["dtc"] = decode_dtc(r[0], r[1])
+        for name, pid, nbytes, dec, unit in svc.FREEZE_PIDS:
+            dd = self._bytes(self.cmd(f"02{pid}00", timeout=timeout))
+            if 0x42 in dd:
+                payload = dd[dd.index(0x42) + 3:dd.index(0x42) + 3 + nbytes]
+                if len(payload) == nbytes:
+                    try:
+                        out["values"].append((name, dec(payload), unit))
+                    except Exception:
+                        pass
+        return out
+
     def close(self):
         try:
             self.ser.close()