feat(trash): Settings retention field (trash_retention_days, 0=keep forever)

frontend/src/views/SettingsView.vue

@@ -16,6 +16,9 @@ const savingTimezone = ref(false);
 const timezoneSaved = ref(false);
 const autoConsolidateTasks = ref(true);
 const savingAutoConsolidate = ref(false);
+const trashRetentionDays = ref("90");
+const savingRetention = ref(false);
+const retentionSaved = ref(false);
 
 async function saveAutoConsolidate() {
   savingAutoConsolidate.value = true;
@@ -52,6 +55,22 @@ async function saveTimezone() {
     savingTimezone.value = false;
   }
 }
+
+async function saveRetention() {
+  const n = Math.max(0, Math.floor(Number(trashRetentionDays.value) || 0));
+  trashRetentionDays.value = String(n);
+  savingRetention.value = true;
+  retentionSaved.value = false;
+  try {
+    await apiPut('/api/settings', { trash_retention_days: String(n) });
+    retentionSaved.value = true;
+    setTimeout(() => (retentionSaved.value = false), 2000);
+  } catch {
+    toastStore.show('Failed to save retention setting', 'error');
+  } finally {
+    savingRetention.value = false;
+  }
+}
 const newEmail = ref("");
 const emailPassword = ref("");
 const changingEmail = ref(false);
@@ -383,6 +402,7 @@ onMounted(async () => {
   // Load notification preferences from user settings
   const allSettings = await apiGet<Record<string, string>>("/api/settings");
   userTimezone.value = allSettings.user_timezone ?? "";
+  trashRetentionDays.value = allSettings.trash_retention_days ?? "90";
   // Default true if unset; explicit "false" disables auto-consolidation.
   autoConsolidateTasks.value = (allSettings.auto_consolidate_tasks ?? "true") !== "false";
   if (allSettings.notify_task_reminders !== undefined) {
@@ -1021,6 +1041,31 @@ function formatUserDate(iso: string): string {
         </div>
       </section>
 
+      <!-- Trash retention -->
+      <section class="settings-section full-width">
+        <h2>Trash retention</h2>
+        <p class="section-desc">Deleted items move to <router-link to="/trash">Trash</router-link> and can be restored. They're permanently purged after this many days.</p>
+        <div class="field">
+          <label for="trash-retention">Retention period (days)</label>
+          <input
+            id="trash-retention"
+            v-model="trashRetentionDays"
+            type="number"
+            min="0"
+            step="1"
+            class="input"
+            style="max-width: 8rem"
+          />
+          <p class="field-hint">Set to <strong>0</strong> to keep deleted items forever (never auto-purge).</p>
+        </div>
+        <div class="actions">
+          <button class="btn-save" @click="saveRetention" :disabled="savingRetention">
+            {{ savingRetention ? 'Saving…' : 'Save' }}
+          </button>
+          <span v-if="retentionSaved" class="saved-msg">Saved!</span>
+        </div>
+      </section>
+
     </div>
 
     <!-- ── Account ── -->