fix: round €/m² in Telegram, drop "Bilder nachladen" admin button, fix lightbox visibility

- notifications: round sqm_price to whole € in Telegram match messages
  (was emitting raw float like "12.345614 €/m²").

- wohnungen: remove the admin-only "Bilder nachladen (N)" button. It
  flickered into view whenever a freshly-scraped flat was still in
  pending state, which was effectively random from the user's point of
  view, and the manual backfill it triggered isn't needed anymore — new
  flats are auto-enriched at scrape time. Also drops the dead helpers
  it was the sole caller of: enrichment.kick_backfill,
  enrichment._backfill_runner, db.flats_needing_enrichment,
  db.enrichment_counts.

- lightbox: the modal didn't appear because Tailwind's Play CDN injects
  its own .hidden { display: none } rule at runtime, which kept fighting
  our class toggle. Switch the show/hide to inline style.display so no
  external stylesheet can mask it. Single-class .lightbox now only owns
  the layout — the initial-hidden state is on the element via
  style="display:none".

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

web/routes/wohnungen.py

@@ -79,7 +79,6 @@ def _wohnungen_context(user) -> dict:
         flats_view.append({"row": f, "last": latest_apps.get(f["id"])})
 
     rejected_view = db.rejected_flats(uid)
-    enrichment_counts = db.enrichment_counts()
 
     partner = db.get_partner_user(uid)
     partner_info = None
@@ -133,7 +132,6 @@ def _wohnungen_context(user) -> dict:
         "flats": flats_view,
         "rejected_flats": rejected_view,
         "filtered_out_flats": filtered_out_view,
-        "enrichment_counts": enrichment_counts,
         "partner": partner_info,
         "map_points": map_points,
         "has_filters": _has_filters(filters_row),
@@ -360,19 +358,6 @@ async def action_submit_forms(
     return RedirectResponse(request.headers.get("referer", "/einstellungen/profil"), status_code=303)
 
 
-@router.post("/actions/enrich-all")
-async def action_enrich_all(
-    request: Request,
-    csrf: str = Form(...),
-    admin=Depends(require_admin),
-):
-    require_csrf(admin["id"], csrf)
-    queued = enrichment.kick_backfill()
-    db.log_audit(admin["username"], "enrichment.backfill",
-                 f"queued={queued}", user_id=admin["id"], ip=client_ip(request))
-    return _wohnungen_partial_or_redirect(request, admin)
-
-
 @router.post("/actions/enrich-flat")
 async def action_enrich_flat(
     request: Request,