feat(moon): the moon with any background, and its status in General settings (#718)

The owner decided on 30.09 that the moon is not part of the "Follow the Sun"
environment but a switch of its own: with a static background (global or a
space's own) the card showed no moon even with the switch on, and the switch
said nothing about why the moon was missing right now.

With a static background there is no environment, so the moon stands in its
own layer, `.hp-moon-sky`: the first child of `.stage` / `.hp-static-stage`,
the whole scene, no z-index, filter or will-change, under the plan by DOM
order, fading with the #101 View weight. Inside is the very #661 element, so
place, size, art and fades are unchanged, and a background switch moves it to
its new parent in the same render without a flicker. The phase comes from the
same `resolveDayCycle`, computed only while the moon is on and on View; without
`sun.sun` both cards keep their 30 s clock ticker and re-render only when the
phase changes (the environment is still compared by its whole fingerprint).

General settings get a second caption line under the moon switch
(`data-moon-status`): one snapshot per opening, judged by the lazy chunk as if
the switch were on, first reason wins (no home, day, below 3°, under 3 %),
numbers rounded and clamped below the threshold they missed. `moonStatus`
decides "shown" with the same `moonShownAt` as the element. It lives in a
WeakMap beside the draft, so it never makes the dialog dirty; a closed
opening's result is dropped. The dialog loads the chunk through the gate's
loader (`withMoon`), now shared by every caller while a load is in flight, so
there is still one fingerprint check and one retry token.

Bundle (same build, against origin/dev): initial View 300 072 -> 300 248 B gzip
(+176 B, under the 500 B of the spec; budget and ceiling not raised); lazy
editor 238 558 -> 238 991 B (+433 B, the line and English strings); lazy moon
11 385 -> 11 712 B (+327 B, layer CSS and status). `src/moon.ts` stays out of
the initial and the editor graph; bundle-budget now refuses an editor/moon
overlap. Monolith metrics: hostRefs 4 885 -> 4 888 — the three `host.` reads of
`src/editors/moon-status.ts` (hass, `_settingsDialog`, requestUpdate) through
its own three-member interface, not the editor port; the other five metrics
are unchanged. houseplan-editor-runtime.ts grows by two lines (import, call).

Tests: AC9/AC10/AC15 and the sky layer in test/moon.test.mjs (the #661
"static -> nothing" check inverted), AC14 and the opening lifecycle in
test/moon-settings.test.mjs, smokes demo/smoke_moon_static.mjs (AC1-AC6; AC1
and AC3 were red on dev) and demo/smoke_moon_status.mjs (AC11/AC12), AC7 in
smoke_daycycle_layer_budget. Golden: two new scenes
(static-bg-moon-gibbous-white-light, static-bg-moon-crescent-south-dark,
matrix v70), the harness checks the moon's parent by background and waits for
the status line in the General settings frames. Four new mutants; the clock
ticker one is a browser guard (201 at the guideline of 200).

Issue: #718
User-Visible: yes
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018qZfe7YS4rqEMKoVeS3GKd

src/editors/general-settings-dialog.ts

@@ -15,6 +15,7 @@ import {
   formCard, segmented, subsection, textLink, toggleRow, unitInput,
 } from './form-kit';
 import { forgetGeneralBaseline, generalDirty, generalProblems, type GeneralSettingsDraft } from './general-form-state';
+import { moonStatusOf, moonStatusText } from './moon-status';
 import { langOf, type I18nKey } from '../i18n';
 import { settingsT, type SettingsI18nKey } from '../i18n/settings';
 import { supportT } from '../i18n/support';
@@ -76,6 +77,8 @@ export function renderGeneralSettingsDialog(this: HouseplanEditorRuntime): Templ
   };
   const glowProblem = problemFor('gs-glow-radius');
   const northProblem = problemFor('gs-north');
+  // #718 K7: the second caption line, once the moon chunk judged this opening.
+  const moonStatus = moonStatusOf(host);
   const zigbeeHelp = hasTopologyTranslation(lang, 'help') && hasTopologyTranslation(lang, 'help_aria')
     ? html`<hp-help data-help-key="topology.help" .text=${topologyT(lang, 'help')} .ariaLabel=${topologyT(lang, 'help_aria')}></hp-help>`
     : nothing;
@@ -227,7 +230,10 @@ export function renderGeneralSettingsDialog(this: HouseplanEditorRuntime): Templ
           ${renderSunRayOriginSegment(d.sunRayOrigin, (key) => t(key), (sunRayOrigin) => set({ sunRayOrigin }))}
           ${toggleRow({
             id: 'gs-moon', icon: 'mdi:moon-waning-crescent',
-            title: st('gs.moon'), caption: st('gs.moon_hint'),
+            title: st('gs.moon'),
+            caption: moonStatus
+              ? html`${st('gs.moon_hint')}<span style="display:block" data-moon-status=${moonStatus.reason}>${moonStatusText(moonStatus, st)}</span>`
+              : st('gs.moon_hint'),
             checked: d.moon, onChange: (v) => set({ moon: v }),
           })}`,
       })}

src/editors/moon-status.ts

@@ -0,0 +1,68 @@
+/**
+ * #718 K7: the «Now: …» line under the moon switch in General settings.
+ *
+ * One snapshot per opening — `now`, `hass.config`, `sun.sun` — judged by the
+ * lazy moon chunk as if the switch were on: the moon no longer depends on the
+ * background, so one status serves the whole installation, whatever the
+ * switch, the background segment or the spaces say. It lives beside the
+ * draft, never in it (`generalDraftKey` does not see it), so the line arriving
+ * does not make the dialog dirty. The result of an opening that was closed in
+ * the meantime is dropped; until the chunk is here, or when it failed, there
+ * is no line and the hint alone stays.
+ */
+import { withMoon } from '../moon-gate';
+import { resolveDayCycle, sunStateOf } from '../sun';
+import type { MoonStatus, MoonStatusReason } from '../moon';
+import type { SettingsI18nKey } from '../i18n/settings';
+
+interface MoonStatusHost {
+  hass?: unknown;
+  _settingsDialog: unknown;
+  requestUpdate(): void;
+}
+
+interface Opening { status?: MoonStatus }
+
+const openings = new WeakMap<object, Opening>();
+
+/** Called by `_openSettingsDialog` once the draft exists: asks for this opening's status. */
+export function openMoonStatus(host: MoonStatusHost, now: Date = new Date()): void {
+  const opening: Opening = {};
+  openings.set(host, opening);
+  const hass = host.hass as { config?: unknown } | undefined;
+  const state = resolveDayCycle(hass, now);
+  // With `source === 'sun'` this is the very elevation `dayCycleSunOf` read.
+  const sun = sunStateOf(hass)?.elevation ?? null;
+  withMoon((moon) => {
+    if (openings.get(host) !== opening || !host._settingsDialog) return;
+    opening.status = moon.moonStatus(hass?.config, state, sun, now);
+    host.requestUpdate();
+  });
+}
+
+/** The status of the current opening, once the chunk has judged it. */
+export function moonStatusOf(host: object): MoonStatus | undefined {
+  return openings.get(host)?.status;
+}
+
+/** Literal keys (#502): the dead-key gate does not read a key glued from the reason. */
+const MOON_STATUS_KEYS: Readonly<Record<MoonStatusReason, SettingsI18nKey>> = {
+  shown: 'gs.moon_status_shown',
+  no_home: 'gs.moon_status_no_home',
+  day_sun: 'gs.moon_status_day_sun',
+  day_clock: 'gs.moon_status_day_clock',
+  low: 'gs.moon_status_low',
+  new: 'gs.moon_status_new',
+};
+
+/** A signed whole number: the minus is U+2212, no plus; −0 reads as 0. */
+const signed = (value = 0): string => (value < 0 ? `−${-value}` : String(Math.abs(value)));
+
+/** The line's text; `st` is the dialog's `settingsT` for its language. */
+export function moonStatusText(
+  status: MoonStatus, st: (key: SettingsI18nKey, vars: Record<string, string>) => string,
+): string {
+  return st(MOON_STATUS_KEYS[status.reason], {
+    alt: signed(status.alt), pct: signed(status.pct), sun: signed(status.sun),
+  });
+}