fix v1.43.0: external audit P0 — data loss, split geometry, auth, dialog zombies

L2 (silent data loss): debounce gains flush()/pending(); _reloadConfigOnly
flushes a pending write and defers while one is in flight; conflict path
forces; failed reload now toasts instead of an empty catch; teardown flushes.

G1 (split corruption): same-edge cuts carve the niche properly instead of
walking the outline twice; partition invariant (parts sum to the original)
rejects anything else; +1 unit test covering 5 niche shapes and both legacy
cut shapes.

B1 (unauthenticated content): plans and marker files move to
HouseplanContentView (/api/houseplan/content/..., requires_auth); only the
card bundle stays static; contentUrl() rewrites legacy URLs on read (no
storage migration); repairs.py accepts both prefixes; +1 unit test.

L3 (dialog zombies): all four save catch-blocks guard against a closed
dialog; the card no longer blanks when a save fails after Esc.

smokes: smoke_save_race, smoke_dialog_zombie; docs (TESTING/CHANGELOG/
ARCHITECTURE incl. the optimistic-UI note) same-commit

demo/smoke_dialog_zombie.mjs

@@ -0,0 +1,55 @@
+import { launch } from './serve.mjs';
+const { page, browser } = await launch();
+const res = await page.evaluate(async () => {
+  const out = {};
+  const c = window.__card;
+  const sr = () => c.shadowRoot || c.renderRoot;
+  let pageError = null;
+  window.addEventListener('error', (e) => { pageError = String(e.message); });
+  // сохранение падает, а диалог закрыт до ответа — карточка не должна умереть
+  c.hass = { ...c.hass, callWS: async (msg) => {
+    if (String(msg.type).endsWith('/set')) { await new Promise((r) => setTimeout(r, 60)); throw new Error('boom'); }
+    return { config: c._serverCfg, rev: c._cfgRev };
+  } };
+  await c.updateComplete;
+  // 1) диалог общих настроек
+  c._openSettingsDialog(); await c.updateComplete;
+  const p = c._saveSettingsDialog();
+  c._settingsDialog = null; // Esc во время сохранения
+  await c.updateComplete;
+  await p.catch(() => {});
+  await new Promise((r) => setTimeout(r, 120));
+  await c.updateComplete;
+  out.settingsStaysClosed = c._settingsDialog === null;
+  out.cardAliveAfterSettings = !!sr().querySelector('.stage');
+  // 2) диалог правил
+  c._openRulesDialog(); await c.updateComplete;
+  const p2 = c._saveRules();
+  c._rulesDialog = null; await c.updateComplete;
+  await p2.catch(() => {});
+  await new Promise((r) => setTimeout(r, 120));
+  await c.updateComplete;
+  out.rulesStaysClosed = c._rulesDialog === null;
+  out.cardAliveAfterRules = !!sr().querySelector('.stage');
+  // 3) диалог устройства
+  c._setMode('devices'); await c.updateComplete;
+  c._openMarkerDialog(c._devices[0]); await c.updateComplete;
+  const p3 = c._saveMarker();
+  c._markerDialog = null; await c.updateComplete;
+  await p3.catch(() => {});
+  await new Promise((r) => setTimeout(r, 120));
+  await c.updateComplete;
+  out.markerStaysClosed = c._markerDialog === null;
+  out.cardAliveAfterMarker = !!sr().querySelector('.stage');
+  out.noPageError = pageError === null;
+  // 4) при ОТКРЫТОМ диалоге ошибка снимает busy (поведение сохранено)
+  c._openSettingsDialog(); await c.updateComplete;
+  const p4 = c._saveSettingsDialog();
+  await p4.catch(() => {});
+  await new Promise((r) => setTimeout(r, 120));
+  out.busyClearedWhenOpen = c._settingsDialog !== null && c._settingsDialog.busy === false;
+  c._settingsDialog = null;
+  return out;
+});
+console.log(JSON.stringify(res, null, 1));
+await browser.close();