UX: Formular-Buttons in Modal-Footer + Kalender-Icons amber

- Alle Formular-Buttons (health, praxen, diary, dog-profile, poison)
  aus dem scrollbaren Body in den festen Modal-Footer verschoben
  (form="form-id" Attribut, btn-Suche via document.querySelector)
- Kalender-Icon Filter korrigiert: brightness(0)+invert(0.55) vermeidet
  Channel-Clipping bei sepia auf Weiß → ergibt echtes Amber (~#C4843A)
- SW-Cache: by-v18 → by-v19

backend/static/js/pages/poison.js

@@ -505,17 +505,17 @@ window.Page_poison = (() => {
                       border-radius:var(--radius-md);margin-top:var(--space-2)">
         </div>
 
-        <div style="display:flex;gap:var(--space-2);margin-top:var(--space-4)">
-          <button type="button" class="btn btn-secondary flex-1"
-                  id="pf-cancel">Abbrechen</button>
-          <button type="submit" class="btn btn-danger flex-1">
-            ⚠️ Meldung abschicken
-          </button>
-        </div>
       </form>
     `;
 
-    UI.modal.open({ title: '⚠️ Giftköder melden', body });
+    const footer = `
+      <button type="button" class="btn btn-secondary flex-1" id="pf-cancel">Abbrechen</button>
+      <button type="submit" form="poison-form" class="btn btn-danger flex-1">
+        ⚠️ Meldung abschicken
+      </button>
+    `;
+
+    UI.modal.open({ title: '⚠️ Giftköder melden', body, footer });
 
     // Standort vorausfüllen wenn bekannt
     if (_userPos) {
@@ -559,7 +559,7 @@ window.Page_poison = (() => {
     // Formular absenden
     document.getElementById('poison-form')?.addEventListener('submit', async e => {
       e.preventDefault();
-      const submitBtn = e.target.querySelector('[type="submit"]');
+      const submitBtn = document.querySelector('[form="poison-form"][type="submit"]') || e.target.querySelector('[type="submit"]');
       const fd        = UI.formData(e.target);
 
       if (!fd.lat || !fd.lon) {