Vacuum first-use path: materialize the marker, count rectangle rooms, fix the toasts

Audit HP-1540-01 (High): an auto-discovered vacuum has no config marker
until the device dialog is saved once, yet the live-position section was
already interactive. setVac, _vacSaveMatrix and auto-calibration all did
cfg.markers.find(...) and silently bailed out — while the auto-calibration
toast still claimed success. Every vacuum edit now materializes a minimal
marker (same id/binding the dialog Save would produce), _vacSaveMatrix
reports whether the write landed, and success toasts are gated on it.

HP-1540-04: the auto-calibration room matcher accepted only polygon rooms
and told users their room names did not match. It goes through the shared
roomPoly() now, so legacy x/y/w/h rectangles count like everywhere else.

HP-1540-06: the no-rooms/no-match/rough-fit toasts pointed at the removed
point calibration; they now point at the fit panel that shipped instead,
and docs/VACUUM.md Setup UX describes the actual UI. Also extracted
vacMapIdFromAttrs as the explicit frontend half of the map-id contract
(backend half lands with HP-1540-02).

Regressions: demo/smoke_vacuum_firstuse.mjs starts from cfg.markers=[]
(the fixture gap the audit called out) with rectangle plan rooms and a
zero map_index, and fails 11 checks on the v1.54.0 bundle; i18n unit test
asserts no point/точк wording in either language.

test/i18n.test.mjs

@@ -25,3 +25,11 @@ test('i18n: placeholders match between languages', () => {
     assert.equal(ph(en[k]), ph(ru[k]), `placeholder mismatch in ${k}`);
   }
 });
+
+test('vac toasts never mention the removed point calibration (HP-1540-06)', () => {
+  for (const [lang, d] of [['en', en], ['ru', ru]]) {
+    for (const k of ['vac.autocal_no_rooms', 'vac.autocal_no_match', 'vac.autocal_res_warn']) {
+      assert.ok(!/point|точк/i.test(d[k]), `${lang}:${k} still points at point calibration`);
+    }
+  }
+});