refactor(#107): theme-state.json → state.json, theme-sync → state-sync

The machine flake's git-tracked settings file is system state, not
"theme" only — rename it to state.json. CLI becomes nomarchy-state-sync
with a nomarchy-theme-sync symlink for scripts and muscle memory.

Eval (mkFlake, doctor, lifecycle) still accepts theme-state.json; the
next write migrates to state.json and removes the legacy file.
Documented in MIGRATION.md; drop the CLI alias after release notes.

modules/home/timezone.nix

@@ -2,7 +2,7 @@
 # timezone. Waybar's clock module captures the zone once at construction, so a
 # runtime timezone change (automatic-timezoned, nomarchy.system.autoTimezone)
 # would NOT show until a relogin. A tiny watcher subscribes to timedate1's
-# change signal and reloads Waybar (SIGUSR2 = the same reload theme-sync uses),
+# change signal and reloads Waybar (SIGUSR2 = the same reload state-sync uses),
 # so the clock follows your location live. Also catches a manual
 # `timedatectl set-timezone`.
 #