fix: change gpiod, i2cd, pcid-spawner to oneshot_async; add pcid-spawner override

All three were blocking the boot scheduler in /usr phase on live-mini
because their daemons never notify readiness without hardware present.

- 00_gpiod.service: scheme -> oneshot_async
- 00_i2cd.service: scheme -> oneshot_async
- 00_pcid-spawner.service: new override, oneshot -> oneshot_async
- base: update submodule to 4a1d1f4 (scheduler counter)

config/redbear-mini.toml

@@ -197,7 +197,7 @@ requires_weak = [
 
 [service]
 cmd = "gpiod"
-type = { scheme = "gpio" }
+type = "oneshot_async"
 """
 
 [[files]]
@@ -211,7 +211,7 @@ requires_weak = [
 
 [service]
 cmd = "i2cd"
-type = { scheme = "i2c" }
+type = "oneshot_async"
 """
 
 [[files]]
@@ -532,3 +532,14 @@ cmd = "getty"
 args = ["/scheme/debug/no-preserve", "-J"]
 type = "oneshot_async"
 """
+
+[[files]]
+path = "/etc/init.d/00_pcid-spawner.service"
+data = """
+[unit]
+description = "PCI driver spawner (non-blocking on live-mini)"
+
+[service]
+cmd = "pcid-spawner"
+type = "oneshot_async"
+"""