feat: persistent logging to logd with /var/log/system.log

logd now writes all log output to /var/log/system.log (5MB auto-rotation)
in addition to existing scheme listeners. Falls back to /tmp/logd-fallback.log
if /var/log is unavailable. Logs survive reboots for post-mortem analysis.
Part of Phase A2 (Boot Reliability) from BOOT-PROCESS-AUDIT-2026-05-03.

recipes/core/base/recipe.toml

@@ -11,6 +11,7 @@ patches = [
     "P3-ps2d-led-feedback.patch",
     "P3-usbhidd-hardening.patch",
     "P3-init-colored-output.patch",
+    "P4-logd-persistent-logging.patch",
 ]
 
 [build]