Add GPS + PPS distribution sheet (all rev-A blocks captured)

- New carrier/GPS_PPS.kicad_sch via tools/build_gps.py: J_GPS 5-pin
  (PPS + UART2 NMEA + 3V3_AUX + GND) per Pinout_BOM section 6
- PPS chain: GPS_PPS_RAW -> PESD3V3L1BA TVS -> 74LVC1G17 Schmitt
  (+3V3_AUX) -> PPS_CLEAN -> 33R series -> SYNC_OUT (CM5 pin 18 + J2.6),
  plus J_PPS1 (UWB) / J_PPS2 (scope) 2-pin taps; board is PPS sink only
- NMEA on UART2 (GPIO4/GPIO5) per correction C2; debug console keeps UART0
- Converted SYNC_OUT/GPIO4/GPIO5 local labels on CM5_GPIO to global
  (names unchanged) to reach the new sheet; root sheet-symbol needs no pins
- J_GPS pins 1/2 typed output (GPS drives PPS/TX) for driver-aware checks
- Verify: ERC 133->133 zero new; analyzer +73/-0 zero regressions; netlist
  confirms all cross-sheet nets; SPICE 24 pass / 2 benign warn / 0 fail

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

carrier/CM5IO.kicad_sch

@@ -3489,6 +3489,16 @@
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 		(uuid "f1109a7e-4bfb-54f4-a32e-e6719bad4ba8")
 	)
+	(sheet
+		(at 205 90)
+		(size 30 20)
+		(stroke (width 0.1524) (type solid) (color 132 0 132 1))
+		(fill (color 255 255 255 0.0000))
+		(uuid "5efffb63-edbb-5986-86d3-84ead412bc65")
+		(property "Sheetname" "GPS_PPS" (at 205 86.18 0) (effects (font (size 1.27 1.27)) (justify left bottom)))
+		(property "Sheetfile" "GPS_PPS.kicad_sch" (at 205 87.45 0) (effects (font (size 1.27 1.27)) (justify left top)))
+		(instances (project "CM5IO" (path "/e63e39d7-6ac0-4ffd-8aa3-1841a4541b55" (page "6"))))
+	)
 	(sheet_instances
 		(path "/"
 			(page "1")