refactor: rename uses_3v3 to uses_vapwr

The flag enables a second power supply (VAPWR), not necessarily 3.3V (gf180's core is already 3v3), so "uses_3v3" no longer accurately describes its purpose.
Rename it across project_info, precheck, project and shuttle, and update the validation message accordingly.

The legacy "uses_3v3" key is still accepted when reading info.yaml, so existing project configs keep working.

precheck/tech_data.py

@@ -96,12 +96,12 @@ valid_layers_gf180mcuD = [
 # fmt: on
 
 
-def analog_pin_rects(tech: str, uses_3v3: bool):
+def analog_pin_rects(tech: str, uses_vapwr: bool):
     if tech == "sky130A":
         pin_layer = (71, 20)  # met4
         via_layers = [(70, 44)]  # via3
         for pin_number in range(8):
-            if uses_3v3:
+            if uses_vapwr:
                 x1, y1 = 136.17 - 19.32 * pin_number, 0.0
             else:
                 x1, y1 = 151.81 - 19.32 * pin_number, 0.0
@@ -112,7 +112,7 @@ def analog_pin_rects(tech: str, uses_3v3: bool):
         pin_layer = (126, 0)  # TopMetal1
         via_layers = [(125, 0)]  # TopVia1
         for pin_number in range(8):
-            if uses_3v3:
+            if uses_vapwr:
                 raise NotImplementedError
             else:
                 x1, y1 = 190.165 - 24.48 * pin_number, 0.0
@@ -123,7 +123,7 @@ def analog_pin_rects(tech: str, uses_3v3: bool):
         pin_layer = (46, 0)  # Metal4
         via_layers = [(40, 0)]  # Via3
         for pin_number in range(8):
-            if uses_3v3:
+            if uses_vapwr:
                 x1, y1 = 307.90 - 43.68 * pin_number, 0.0
             else:
                 x1, y1 = 325.82 - 43.68 * pin_number, 0.0