feat(catalog): supplier catalog cleanup, fuzzy matching, and navigation fixes

- Cleaned 137+ fake engine-displacement models from supplier imports
  (v3/v4 scripts: Chevrolet, Ford, Chrysler, Dodge, Jeep, Nissan, etc.)
- Removed 1,251+ corrupted models (INT. prefixes, year-suffix, torque specs,
  empty names, trailing-year variants)
- Migrated supplier tables to master DB (supplier_catalog,
  supplier_catalog_compat, supplier_catalog_interchange)
- Fixed _get_mye_ids_with_parts() to query supplier_catalog_compat from
  master DB so supplier-only vehicles appear for all tenants
- Added fuzzy model matcher with parenthesis stripping, noise suffix removal,
  compact matching, prefix/substring fallback, model aliases, and ±3 year
  proximity
- Matched compat rows: KEEP GREEN +14,152, KNADIAN +3,021, VAZLO +127,500,
  LUK +477, RAYBESTOS +1,743
- Added KNADIAN catalog importer with year-range expansion and future-year
  filtering
- Added VAZLO catalog importer with position parsing and SKU-in-model cleanup
- Added Keep Green, LUK, Yokomitsu, Raybestos catalog importers
- Cache clearing after cleanups (_classify_cache_*, nexus:mye_ids:*,
  nexus:brand_mye_counts:*)

Final match rates:
- KEEP GREEN: 90.3%
- VAZLO: 93.6%
- YOKOMITSU: 100.0%
- KNADIAN: 57.4%
- LUK: 51.0%
- RAYBESTOS: 55.9%

pos/templates/marketplace_external.html

@@ -184,6 +184,9 @@
         <button class="tab-btn" role="tab" aria-selected="false" aria-controls="panel-orders" onclick="switchTab('orders')">
           Órdenes
         </button>
+        <button class="tab-btn" role="tab" aria-selected="false" aria-controls="panel-questions" onclick="switchTab('questions')">
+          Preguntas
+        </button>
       </div>
 
       <!-- Tab Panels -->
@@ -262,6 +265,27 @@
           <div id="listingsPagination" class="table-footer" style="margin-top:var(--space-4);"></div>
         </div>
 
+        <!-- ══════════ TAB: Preguntas ══════════ -->
+        <div class="tab-panel" id="panel-questions" role="tabpanel">
+          <div class="toolbar">
+            <div class="search-box">
+              <svg viewBox="0 0 24 24" stroke-linecap="round"><circle cx="11" cy="11" r="8"/><line x1="21" y1="21" x2="16.65" y2="16.65"/></svg>
+              <input type="text" id="questionSearch" placeholder="Buscar pregunta..." oninput="filterQuestions()" />
+            </div>
+            <select class="select-filter" id="questionStatusFilter" onchange="filterQuestions()">
+              <option value="">Todas</option>
+              <option value="unanswered">Sin responder</option>
+              <option value="answered">Respondidas</option>
+              <option value="closed">Cerradas</option>
+            </select>
+            <div class="toolbar__spacer"></div>
+            <button class="btn btn--ghost btn--sm" onclick="syncQuestions()">🔄 Sincronizar con ML</button>
+            <button class="btn btn--primary" onclick="loadQuestions()">🔄 Actualizar</button>
+          </div>
+          <div id="questionsStatsBar" style="margin-bottom:var(--space-4);"></div>
+          <div id="questionsContainer" class="meli-grid"></div>
+        </div>
+
         <!-- ══════════ TAB: Órdenes ══════════ -->
         <div class="tab-panel" id="panel-orders" role="tabpanel">
           <div class="toolbar">