fix(admin): issue #131 — dead callback buttons prod_district_/admin_users + no-op placeholders

- prod_district_: pipe-delimited format (multi-word names safe) + handleDistrictBack shows categories (admin sees disabled locations via getLocationsByCountryAndCityAdmin)
- admin_users: handleUserListBack (viewUserPage(0) edit)
- current_page/current_quantity/no_action: no-op exact routes (no 'No handler' warns)
- Audit: all 78 generated callbacks cross-checked — no overlaps, none missing
- 48 tests pass; bump v1.2.6

src/admin/views/partials/app-sidebar.ejs

@@ -28,7 +28,7 @@
             <svg class="sa-icon sa-thin">
                 <use href="/icons/sprite.svg#tag"></use>
             </svg>
-            <span class="fs-xs opacity-70">v1.2.5</span>
+            <span class="fs-xs opacity-70">v1.2.6</span>
         </div>
     </div>
 </aside>
@@ -43,10 +43,10 @@
             </div>
             <div class="modal-body">
                 <div class="alert alert-info mb-3">
-                    <strong>Current:</strong> v1.2.5 &middot; 2026-08-05
+                    <strong>Current:</strong> v1.2.6 &middot; 2026-08-05
                 </div>
 
-                <h6 class="fw-bold mb-2">v1.2.5 <span class="text-muted fs-sm">&mdash; 2026-08-05</span></h6>
+                <h6 class="fw-bold mb-2">v1.2.6 <span class="text-muted fs-sm">&mdash; 2026-08-05</span></h6>
                 <ul class="small mb-3">
                     <li><span class="badge bg-info">refactor</span> Removed deposit amount-selection step; deposit_wallet_ now goes directly to Mercuryo instructions</li>
                     <li><span class="badge bg-primary">feat</span> Updated Mercuryo button text to include VISA/Mastercard branding in all locales</li>

src/handlers/adminHandlers/adminUserHandler.js

@@ -184,6 +184,26 @@ export default class AdminUserHandler {
         }
     }
 
+    static async handleUserListBack(callbackQuery) {
+        if (!isAdmin(callbackQuery.from.id)) {
+            return;
+        }
+
+        const chatId = callbackQuery.message.chat.id;
+
+        try {
+            const {text, markup} = await this.viewUserPage(0);
+            await bot.editMessageText(text, {
+                chat_id: chatId,
+                message_id: callbackQuery.message.message_id,
+                reply_markup: markup,
+                parse_mode: 'HTML'
+            });
+        } catch (e) {
+            return;
+        }
+    }
+
     static async handleViewUser(callbackQuery) {
         if (!isAdmin(callbackQuery.from.id)) return;
     

src/handlers/adminHandlers/product/categoryAddHandler.js

@@ -44,7 +44,7 @@ export default class CategoryAddHandler {
                         inline_keyboard: [[
                             {
                                 text: '« Back to Categories',
-                                callback_data: `prod_district_${location.country}_${location.city}_${location.district}`
+                                callback_data: `prod_district_${encodeURIComponent(location.country)}|${encodeURIComponent(location.city)}|${encodeURIComponent(location.district)}`
                             }
                         ]]
                     }
@@ -83,7 +83,7 @@ export default class CategoryAddHandler {
                 message_id: callbackQuery.message.message_id,
                 reply_markup: {
                     inline_keyboard: [[
-                        {text: '❌ Cancel', callback_data: `prod_district_${location.country}_${location.city}_${location.district}`}
+                        {text: '❌ Cancel', callback_data: `prod_district_${encodeURIComponent(location.country)}|${encodeURIComponent(location.city)}|${encodeURIComponent(location.district)}`}
                     ]]
                 }
             }

src/handlers/adminHandlers/product/districtHandler.js

@@ -45,6 +45,51 @@ export default class DistrictHandler {
         }
     }
 
+    static async handleDistrictBack(callbackQuery) {
+        if (!isAdmin(callbackQuery.from.id)) {
+            return;
+        }
+
+        const chatId = callbackQuery.message.chat.id;
+        const messageId = callbackQuery.message.message_id;
+        const payload = callbackQuery.data.replace('prod_district_', '');
+        const [country, city, district] = payload.split('|').map(decodeURIComponent);
+
+        try {
+            const all = await LocationService.getLocationsByCountryAndCityAdmin(country, city);
+            const location = all.find(l => l.district === district);
+
+            if (!location) {
+                throw new Error('Location not found');
+            }
+
+            const categories = await CategoryService.getCategoriesByLocationId(location.id);
+
+            const keyboard = {
+                inline_keyboard: [
+                    ...categories.map(cat => [{
+                        text: cat.name,
+                        callback_data: `prod_category_${location.id}_${cat.id}`
+                    }]),
+                    [{text: '➕ Add Category', callback_data: `add_category_${location.id}`}],
+                    [{text: '« Back', callback_data: `prod_city_${encodeURIComponent(country)}|${encodeURIComponent(city)}`}]
+                ]
+            };
+
+            await bot.editMessageText(
+                '📦 Select or add category:',
+                {
+                    chat_id: chatId,
+                    message_id: messageId,
+                    reply_markup: keyboard
+                }
+            );
+        } catch (error) {
+            logger.error({ err: error }, 'Error in handleDistrictBack');
+            await editOrSendCallback(callbackQuery, 'Error loading categories. Please try again.');
+        }
+    }
+
     static async handleDistrictSelection(callbackQuery) {
         if (!isAdmin(callbackQuery.from.id)) {
             return;

src/handlers/adminHandlers/product/index.js

@@ -16,6 +16,7 @@ export default {
     handleCountrySelection: NavigationHandler.handleCountrySelection,
     handleCitySelection: DistrictHandler.handleCitySelection,
     handleDistrictSelection: DistrictHandler.handleDistrictSelection,
+    handleDistrictBack: DistrictHandler.handleDistrictBack,
     handleCategoryInput: CategoryAddHandler.handleCategoryInput,
     handleAddCategory: CategoryAddHandler.handleAddCategory,
     handleCategoryUpdate: CategoryEditHandler.handleCategoryUpdate,

src/router/routes.js

@@ -55,6 +55,14 @@ export function registerRoutes() {
         await userHandler.handleSetLanguage(cq);
     });
 
+    // === No-op Placeholder Buttons ===
+    const noopActions = ['current_page', 'current_quantity', 'no_action'];
+    for (const action of noopActions) {
+        callbackRouter.registerExact(action, async () => {
+            // Placeholder button — nothing to do
+        });
+    }
+
     // === Text Commands ===
     messageRouter.registerText('keyboard.products', async (msg) => {
         if (shouldDebounceMainMenu(msg.chat.id, 'keyboard.products')) return;
@@ -207,6 +215,10 @@ export function registerRoutes() {
         logDebug(cq.data, 'handleBackToWalletTypes');
         await adminWalletsHandler.handleBackToWalletTypes(cq);
     });
+    callbackRouter.registerExact('admin_users', async (cq) => {
+        logDebug(cq.data, 'handleUserListBack');
+        await adminUserHandler.handleUserListBack(cq);
+    });
 
     // === Prefix Callback Routes ===
     callbackRouter.registerPrefix('set_country_', async (cq) => {
@@ -297,6 +309,10 @@ export function registerRoutes() {
         logDebug(cq.data, 'handleDistrictSelection');
         await productHandler.handleDistrictSelection(cq);
     });
+    callbackRouter.registerPrefix('prod_district_', async (cq) => {
+        logDebug(cq.data, 'handleDistrictBack');
+        await productHandler.handleDistrictBack(cq);
+    });
     callbackRouter.registerPrefix('add_category_', async (cq) => {
         logDebug(cq.data, 'handleAddCategory');
         await productHandler.handleAddCategory(cq);

src/services/locationService.js

@@ -27,6 +27,13 @@ class LocationService {
         );
     }
 
+    static async getLocationsByCountryAndCityAdmin(country, city) {
+        return await db.allAsync(
+            'SELECT id, country, city, district FROM locations WHERE country = ? AND city = ? ORDER BY district',
+            [country, city]
+        );
+    }
+
     static async getLocation(country, city, district) {
         try {
             const location = await db.getAsync(