wohnungen: preserve map across HTMX polls, add rejected section, drop €/m²

- #flats-map uses hx-preserve; marker data moved to <script type="application/json">
  sibling that diffs+updates instead of rebuilding Leaflet every poll (fixes
  whitescreen + tiles rendering outside the card)
- upsert_flat backfills lat/lng on existing rows missing coords (older flats
  scraped before the lat/lng migration now appear on the map once alert re-submits)
- collapsible "Abgelehnte Wohnungen" section at the bottom with Wiederherstellen
- remove €/m² column from the list

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/static/map.js

@@ -1,17 +1,75 @@
-// lazyflat — Leaflet flat map
-// Initialised LAZILY: we only build the Leaflet instance when the container
-// actually has a rendered size (> 0 height). Building it on a hidden 0×0
-// container leaves Leaflet in a state where tiles never load.
+// lazyflat — Leaflet flat map.
+//
+// Two important properties:
+// 1. The map must only be *built* once the container has a real size, because
+//    Leaflet initialised on a hidden 0×0 element never loads its tiles.
+// 2. The `#wohnungen-body` partial is re-swapped by HTMX every few seconds.
+//    To avoid rebuilding Leaflet (and all its tile/marker state) on every
+//    poll — which caused the whitescreen + out-of-frame glitches — the map
+//    container itself is preserved across swaps via `hx-preserve`, and the
+//    marker data is pushed in through a sibling <script id="flats-map-data">
+//    element that DOES get swapped. On each swap we diff markers against the
+//    fresh data and update in place.
 
 let mapInstance = null;
+let markerLayer = null;
+let currentFingerprint = "";
 const BERLIN_CENTER = [52.52, 13.405];
 const BERLIN_ZOOM = 11;
 
-function buildMap(el) {
-  if (mapInstance) {
-    try { mapInstance.remove(); } catch (e) {}
-    mapInstance = null;
+function readMapData() {
+  const script = document.getElementById("flats-map-data");
+  if (!script) return [];
+  try {
+    const data = JSON.parse(script.textContent || "[]");
+    return Array.isArray(data) ? data : [];
+  } catch (e) {
+    return [];
   }
+}
+
+function fingerprintOf(data) {
+  return data
+    .map((f) => `${f.lat},${f.lng},${f.address || ""},${f.rent || ""}`)
+    .join("|");
+}
+
+function renderMarkers(data) {
+  if (!mapInstance) return;
+  const fp = fingerprintOf(data);
+  if (fp === currentFingerprint) return;
+  currentFingerprint = fp;
+
+  if (markerLayer) {
+    markerLayer.clearLayers();
+  } else {
+    markerLayer = L.layerGroup().addTo(mapInstance);
+  }
+
+  const bounds = [];
+  data.forEach((f) => {
+    if (typeof f.lat !== "number" || typeof f.lng !== "number") return;
+    const rent = f.rent ? Math.round(f.rent) + " €" : "";
+    const rooms = f.rooms ? f.rooms + " Zi" : "";
+    const size = f.size ? Math.round(f.size) + " m²" : "";
+    const meta = [rooms, size, rent].filter(Boolean).join(" · ");
+    const safeAddr = (f.address || "").replace(/</g, "&lt;");
+    const safeLink = (f.link || "#").replace(/"/g, "&quot;");
+    L.marker([f.lat, f.lng]).addTo(markerLayer).bindPopup(
+      `<b>${safeAddr}</b>` + (meta ? `<br>${meta}` : "") +
+      `<br><a href="${safeLink}" target="_blank" rel="noopener">Zur Anzeige →</a>`,
+    );
+    bounds.push([f.lat, f.lng]);
+  });
+
+  if (bounds.length === 1) {
+    mapInstance.setView(bounds[0], 14);
+  } else if (bounds.length > 1) {
+    mapInstance.fitBounds(bounds, { padding: [30, 30] });
+  }
+}
+
+function buildMap(el) {
   mapInstance = L.map(el, {
     zoomControl: false,
     scrollWheelZoom: false,
@@ -25,45 +83,30 @@ function buildMap(el) {
     maxZoom: 18,
     subdomains: "abc",
   }).addTo(mapInstance);
-
-  let data = [];
-  try { data = JSON.parse(el.dataset.flats || "[]"); } catch (e) {}
-  const bounds = [];
-  data.forEach((f) => {
-    if (typeof f.lat !== "number" || typeof f.lng !== "number") return;
-    const rent = f.rent ? Math.round(f.rent) + " €" : "";
-    const rooms = f.rooms ? f.rooms + " Zi" : "";
-    const size = f.size ? Math.round(f.size) + " m²" : "";
-    const meta = [rooms, size, rent].filter(Boolean).join(" · ");
-    const safeAddr = (f.address || "").replace(/</g, "&lt;");
-    const safeLink = (f.link || "#").replace(/"/g, "&quot;");
-    L.marker([f.lat, f.lng]).addTo(mapInstance).bindPopup(
-      `<b>${safeAddr}</b>` + (meta ? `<br>${meta}` : "") +
-      `<br><a href="${safeLink}" target="_blank" rel="noopener">Zur Anzeige →</a>`,
-    );
-    bounds.push([f.lat, f.lng]);
-  });
-  if (bounds.length === 1) {
-    mapInstance.setView(bounds[0], 14);
-  } else if (bounds.length > 1) {
-    mapInstance.fitBounds(bounds, { padding: [30, 30] });
-  }
+  markerLayer = L.layerGroup().addTo(mapInstance);
 }
 
 function ensureMap() {
   const el = document.getElementById("flats-map");
   if (!el || typeof L === "undefined") return;
 
-  // Container not actually visible yet → bail, we'll retry when the view toggles.
+  // Hidden (0×0) container → tiles would never load; retry after view toggle.
   if (el.clientHeight < 10) return;
 
-  // Existing instance bound to THIS element → just recheck size.
-  if (mapInstance && mapInstance._container === el) {
+  if (!mapInstance) {
+    buildMap(el);
+  } else if (mapInstance._container !== el) {
+    // Container node changed (shouldn't happen thanks to hx-preserve, but
+    // defensive: rebuild so Leaflet rebinds to the live element).
+    try { mapInstance.remove(); } catch (e) {}
+    mapInstance = null;
+    markerLayer = null;
+    currentFingerprint = "";
+    buildMap(el);
+  } else {
     try { mapInstance.invalidateSize(); } catch (e) {}
-    return;
   }
-
-  buildMap(el);
+  renderMarkers(readMapData());
 }
 
 function wireViewToggle() {
@@ -72,9 +115,7 @@ function wireViewToggle() {
     r.dataset.wired = "1";
     r.addEventListener("change", (e) => {
       try { localStorage.setItem("lazyflat_view_mode", e.target.value); } catch (err) {}
-      // Wait for CSS :has() to reflow, then build/size the map.
       requestAnimationFrame(() => requestAnimationFrame(ensureMap));
-      // belt & suspenders — re-check a couple more times in case of layout shifts.
       setTimeout(ensureMap, 120);
       setTimeout(ensureMap, 400);
     });
@@ -88,7 +129,6 @@ function restoreView() {
   const el = document.querySelector(`input[name="view_mode"][value="${stored}"]`);
   if (el && !el.checked) {
     el.checked = true;
-    // Manually dispatching change would bubble and double-fire; call directly.
     requestAnimationFrame(() => requestAnimationFrame(ensureMap));
     setTimeout(ensureMap, 120);
     setTimeout(ensureMap, 400);
@@ -98,7 +138,7 @@ function restoreView() {
 function onReady() {
   wireViewToggle();
   restoreView();
-  ensureMap();  // handles the case where map view is already visible
+  ensureMap();
 }
 
 document.addEventListener("DOMContentLoaded", onReady);