Support multiple deploy template list URLs with cross-list dedupe

Add Settings UI to configure many Portainer-format template catalogs (not just one), merge them on fetch, drop duplicates by image/stack/title, and show source counts on the Deploy view.

index.html

@@ -1530,6 +1530,28 @@ services:
           </div>
           <button type="button" class="btn btn-primary btn-sm mt-3" id="settings-save-btn">Save preferences</button>
         </div>
+        <div class="settings-section">
+          <h3>Deploy template lists</h3>
+          <p class="small text-muted mb-2">
+            Portainer-format JSON catalogs (<code>templates.json</code>). Add as many as you want — peardock merges them and removes duplicates (same image / stack repo / title). Portainer only allows one list.
+          </p>
+          <ul id="settings-template-urls" class="list-group list-group-flush mb-2 settings-template-urls"></ul>
+          <div class="input-group input-group-sm mb-2">
+            <input type="url" id="settings-template-url-input" class="form-control bg-dark text-white font-monospace" placeholder="https://example.com/templates.json" spellcheck="false" autocomplete="off">
+            <button type="button" class="btn btn-outline-primary" id="settings-template-url-add" title="Add list URL">
+              <i class="fas fa-plus me-1"></i>Add
+            </button>
+          </div>
+          <div class="d-flex flex-wrap gap-2">
+            <button type="button" class="btn btn-outline-secondary btn-sm" id="settings-template-url-reset" title="Restore default catalog">
+              Restore default
+            </button>
+            <button type="button" class="btn btn-outline-info btn-sm" id="settings-template-reload" title="Fetch all lists now">
+              <i class="fas fa-sync me-1"></i>Reload templates
+            </button>
+          </div>
+          <div id="settings-template-lists-status" class="small text-muted mt-2"></div>
+        </div>
         <div class="settings-section">
           <h3>Active peer</h3>
           <div id="settings-peer-info" class="small text-muted">Not connected</div>