touch: P4 GPS probe — per-constellation view, and trim the boot cost to 1.2s

Follow-up to 6430866. Two changes.

Print one example of each distinct NMEA sentence type, not just the first line.
A single GxGSV is not enough to judge satellite visibility: the first boot showed
"$GLGSV,1,1,00" and I read that as zero satellites, but GLGSV is GLONASS ONLY and
says nothing about GPS, Galileo or BeiDou. The full set showed 10 GPS + 5 GLONASS
in view with SNR 33/35/23, plus "$GPTXT,...,ANTENNA OK" from the module's own
antenna check, i.e. a healthy receiver mid-acquisition rather than a fault.

Shorten the drain from 3s to 1.2s. It runs on EVERY boot and it consumes bytes
the NMEA parser would otherwise see, so it only needs to be long enough to catch
one of each sentence type (the L76K repeats the full set about once a second).
1.2s still captured all nine types on the verification run.

Confirmed working on hardware: a later boot reported
  $GNGGA,073620.000,5050.80018,N,00452.95932,E,1,05,2.2,36.0,M
  $GNGSA,A,3,08,22,32,...,2.2
i.e. a valid 3D fix on 5 satellites at HDOP 2.2, down from no fix / HDOP 25.5 a
few minutes earlier. The GPS path was never broken; the old diagnostic just could
not tell anyone that, because it reported a flag ENV_SKIP_GPS_DETECT forces true.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tdisplay_p4/main/main.cpp

@@ -247,12 +247,18 @@ static void wadameshSetup() {
     for (int i = 0; i < sensors.getNumSettings(); i++)
       if (strcmp(sensors.getSettingName(i), "gps") == 0) has_setting = true;
 
-    // Drain up to 3 s of NMEA. Bytes at all => pins, rails, wake and baud are ALL correct and a
-    // stuck "acquiring" is a FIX problem (antenna / sky view). Zero bytes => the link is dead.
+    // Drain a SHORT window of NMEA. Bytes at all => pins, rails, wake and baud are ALL correct and
+    // a stuck "acquiring" is a FIX problem (antenna / sky view). Zero bytes => the link is dead.
+    // 1.2 s, not longer: this runs on every boot and it CONSUMES bytes the NMEA parser would
+    // otherwise see, so it is deliberately just long enough to catch one of each sentence type
+    // (the L76K repeats the full set about once a second).
     uint32_t bytes = 0, lines = 0;
     char first[96]; first[0] = '\0';
     char cur[96];   size_t cl = 0;
-    const uint32_t until = millis() + 3000;
+    // Keep one example of each distinct GSV/GGA/RMC talker so every constellation is represented
+    // without dumping the whole stream (the same 5 sentence types repeat every second).
+    char kept[10][96]; int kept_n = 0;
+    const uint32_t until = millis() + 1200;
     while ((int32_t)(millis() - until) < 0) {
       while (Serial1.available() > 0) {
         const int c = Serial1.read();
@@ -263,6 +269,12 @@ static void wadameshSetup() {
             cur[cl] = '\0';
             ++lines;
             if (!first[0] && cur[0] == '$') { strncpy(first, cur, sizeof first - 1); first[sizeof first - 1] = '\0'; }
+            // Keep the first of each sentence TYPE (talker + type, e.g. "$GPGSV", "$GNGGA").
+            if (cur[0] == '$' && cl >= 6 && kept_n < 10) {
+              bool seen = false;
+              for (int k = 0; k < kept_n; ++k) if (strncmp(kept[k], cur, 6) == 0) { seen = true; break; }
+              if (!seen) { strncpy(kept[kept_n], cur, sizeof kept[0] - 1); kept[kept_n][sizeof kept[0] - 1] = '\0'; ++kept_n; }
+            }
             cl = 0;
           }
         } else if (cl < sizeof(cur) - 1) {
@@ -272,11 +284,20 @@ static void wadameshSetup() {
       delay(5);
     }
     printf("[GPS] setting_registered=%d (forced by ENV_SKIP_GPS_DETECT, proves nothing)\n", (int)has_setting);
-    printf("[GPS] UART probe: %lu bytes, %lu lines in 3s @ %d baud, module TX -> GPIO%d\n",
+    printf("[GPS] UART probe: %lu bytes, %lu lines in 1.2s @ %d baud, module TX -> GPIO%d\n",
            (unsigned long)bytes, (unsigned long)lines, (int)GPS_BAUD_RATE, (int)PIN_GPS_TX);
     if (first[0])        printf("[GPS] first sentence: %s\n", first);
     else if (bytes)      printf("[GPS] bytes but no complete '$' sentence -> wrong baud or line noise\n");
     else                 printf("[GPS] NOTHING on the UART -> check wake (XL9535 IO11 HIGH), rails, RX pin\n");
+    // Satellite visibility across ALL constellations, plus the fix line. One GxGSV is not enough:
+    // GLGSV is GLONASS only, so "00" there says nothing about GPS/Galileo/BeiDou. GSV field 3 is
+    // sats-in-view for that constellation; GGA field 6 is fix quality (0 = no fix) and field 7 the
+    // sats used. Non-zero in-view with quality 0 means it IS hearing satellites and just needs
+    // time or better sky. All-zero in-view points at the antenna or shielding.
+    if (kept_n) {
+      printf("[GPS] --- satellite view (%d sentences) ---\n", kept_n);
+      for (int i = 0; i < kept_n; ++i) printf("[GPS]   %s\n", kept[i]);
+    }
   }
   ui_task.begin(disp, &sensors, the_mesh.getNodePrefs());
   board.onBootComplete();