feat(nightlight): geo mode — lat/long-computed sunset via wlsunset

Set BOTH nomarchy.nightlight.latitude/.longitude and the night light
switches backing unit: wlsunset computes sunrise/sunset from the
location daily (the fixed .sunrise/.sunset are ignored;
.temperature feeds the night temp). Everything user-facing is
unchanged — same nomarchy-nightlight toggle script, Waybar moon, and
live-state ExecCondition gate; the unit name is a single let-binding
so all three follow together. Declarative-only on purpose: coordinates
are machine config like the keyboard layout, so home.nix (commented
template example), not a menu writer.

checks.nightlight-geo guards the wiring at pure eval: rendered
wlsunset ExecStart carries the coords + night temperature, the
ExecCondition gate landed on the swapped unit, hyprsunset stays off in
geo mode.

Verification: V1 — nix flake check --no-build exit 0 (evals the new
asserts + option-docs sync); built downstream-template-home (default
hyprsunset path unregressed). V3 pending: visible warm shift at the
location's night + instant toggle/off-persistence on the swapped unit
(HARDWARE-QUEUE § Any machine).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

agent/HARDWARE-QUEUE.md

@@ -224,6 +224,16 @@ the **T14s** (webcam case).
       hibernate — likely no swap is configured. See docs/MIGRATION.md →
       Enabling hibernation."), **not** a silent no-op. (`swapon` after, if you
       swapoff'd for the test.)
+- [ ] **Night-light geo mode (2026-07-11)** — in `home.nix` set
+      `nomarchy.nightlight = { enable = true; latitude = "<lat>";
+      longitude = "<long>"; }` (your real coordinates), `nomarchy-home`,
+      relogin. Then: `systemctl --user status wlsunset` is running (and
+      `hyprsunset` is NOT); after local sunset the screen visibly warms
+      (or test by setting coordinates where it's currently night); the
+      Waybar moon + menu toggle still flip it instantly and an *off*
+      survives relogin (the ExecCondition gate on the swapped unit —
+      the eval check proves the wiring, not the runtime gate). **Pass** =
+      warm shift at the location's night + toggle/persistence intact.
 
 ## AMD dev box only
 - [ ] **AMD runtime bits** — VA-API (`vainfo` → radeonsi), amd-pstate EPP