fix(bot): issue #129 — missing shop_district_/shop_subcategory_ handlers, answerCallbackQuery timing, state.location pipe format

- Register shop_district_ (handleDistrictBack) + shop_subcategory_ (handleSubcategorySelection) in routes.js — Back button in empty categories now works
- state.location pipe-delimited with encodeURIComponent — multi-word names (Saint Petersburg) no longer break nav
- answerCallbackQuery moved to start of callback handling — no stuck spinner
- Empty city fallback (district_unknown) in Select district
- Guard against stale underscore-format state.location
- 48 tests pass; bump v1.2.4

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">v1.2.3</span>
+            <span class="fs-xs opacity-70">v1.2.4</span>
         </div>
     </div>
 </aside>
@@ -43,10 +43,10 @@
             </div>
             <div class="modal-body">
                 <div class="alert alert-info mb-3">
-                    <strong>Current:</strong> v1.2.3 &middot; 2026-08-04
+                    <strong>Current:</strong> v1.2.4 &middot; 2026-08-05
                 </div>
 
-                <h6 class="fw-bold mb-2">v1.2.3 <span class="text-muted fs-sm">&mdash; 2026-08-04</span></h6>
+                <h6 class="fw-bold mb-2">v1.2.4 <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>