fix: udev-shim panic, sessiond duplicate, scheme Bad-fd handling

- udev-shim: replace .expect() with graceful errors (no more panic on Broken pipe)
- P4-initfs: remove duplicate sessiond (conflicted with config)
- accessibility/ime/keymapd: break instead of exit(1) on EBADF
- P6 driver patches rebased
- Docs: archive old reports, add implementation master plan

local/patches/base/P4-initfs-dbus-services.patch

@@ -22,21 +22,11 @@
 +args = ["--system", "--nopidfile"]
 +type = "oneshot_async"
 --- /dev/null
-+++ b/init.d/13_sessiond.service
-@@ -0,0 +1,7 @@
-+[unit]
-+description = "Red Bear session broker"
-+requires_weak = ["12_dbus.service"]
-+
-+[service]
-+cmd = "redbear-sessiond"
-+type = "oneshot_async"
---- /dev/null
 +++ b/init.d/13_seatd.service
 @@ -0,0 +1,8 @@
 +[unit]
 +description = "seatd seat management"
-+requires_weak = ["12_dbus.service", "13_sessiond.service"]
++requires_weak = ["12_dbus.service"]
 +
 +[service]
 +cmd = "/usr/bin/seatd"