Extend MSP_GPSSTATISTICS to include GPS hardware version

Add hwVersion field to MSP_GPSSTATISTICS (166) for GPS module detection:
- Field added at end of message (backward compatible)
- Exposes gpsState.hwVersion (800=M8, 900=M9, 1000=M10, 0=Unknown)
- Enables configurator auto-detection of GPS module type

Changes:
- src/main/fc/fc_msp.c: Add sbufWriteU32(dst, gpsState.hwVersion)
- docs/development/msp/msp_messages.json: Document hwVersion field

Used by configurator GPS preset UI to automatically configure optimal
constellation/rate settings based on hardware capability (M8/M9/M10).

Backward compatible: Old configurators ignore extra bytes, new configurators
check byteLength before reading hwVersion field.

Related configurator PR: feature-gps-preset-ui branch
Research: claude/developer/docs/gps/m9-16-satellite-limitation-official.md

Author: sensei-hacker

docs/development/msp/msp_messages.json

@@ -4896,6 +4896,12 @@
                     "ctype": "uint16_t",
                     "desc": "Estimated Vertical Position Accuracy (`gpsSol.epv`)",
                     "units": "cm"
+                },
+                {
+                    "name": "hwVersion",
+                    "ctype": "uint32_t",
+                    "desc": "GPS hardware version (`gpsState.hwVersion`). Values: 500=UBLOX5, 600=UBLOX6, 700=UBLOX7, 800=UBLOX8, 900=UBLOX9, 1000=UBLOX10, 0=UNKNOWN",
+                    "units": "Version code"
                 }
             ]
         },

src/main/fc/fc_msp.c

@@ -1009,6 +1009,7 @@ static bool mspFcProcessOutCommand(uint16_t cmdMSP, sbuf_t *dst, mspPostProcessF
         sbufWriteU16(dst, gpsSol.hdop);
         sbufWriteU16(dst, gpsSol.eph);
         sbufWriteU16(dst, gpsSol.epv);
+        sbufWriteU32(dst, gpsState.hwVersion);
         break;
 #endif
     case MSP2_ADSB_VEHICLE_LIST: