feat: configurable vehicle compatibility source (TecDoc / QWEN / Both)

Backend:
- Added GET/PUT /pos/api/config/vehicle-compat-source endpoints
- Added get_compat_source() helper reading from tenant_config
- create_item() now respects config: runs TecDoc and/or QWEN accordingly
- auto_match_item_vehicles() respects config: runs only configured source

Frontend:
- Added 'Compatibilidad de Vehiculos' section in config.html
- Added loadVehicleCompatSource() / saveVehicleCompatSource() in config.js
- Regenerated config.min.js

pos/blueprints/config_bp.py

@@ -409,3 +409,45 @@ def upgrade_billing():
     if 'error' in result:
         return jsonify(result), 400
     return jsonify(result)
+
+
+# ─── Vehicle Compatibility Source ────────────────────
+
+@config_bp.route('/vehicle-compat-source', methods=['GET'])
+@require_auth()
+def get_vehicle_compat_source():
+    """Get the configured vehicle compatibility source.
+
+    Returns: {'source': 'tecdoc' | 'qwen' | 'both'}
+    """
+    conn = get_tenant_conn(g.tenant_id)
+    cur = conn.cursor()
+    cur.execute("SELECT value FROM tenant_config WHERE key = 'vehicle_compat_source'")
+    row = cur.fetchone()
+    cur.close()
+    conn.close()
+    source = row[0] if row else 'both'
+    if source not in ('tecdoc', 'qwen', 'both'):
+        source = 'both'
+    return jsonify({'source': source})
+
+
+@config_bp.route('/vehicle-compat-source', methods=['PUT'])
+@require_auth('config.edit')
+def update_vehicle_compat_source():
+    """Set the vehicle compatibility source."""
+    data = request.get_json() or {}
+    source = data.get('source', 'both')
+    if source not in ('tecdoc', 'qwen', 'both'):
+        return jsonify({'error': 'source must be tecdoc, qwen, or both'}), 400
+
+    conn = get_tenant_conn(g.tenant_id)
+    cur = conn.cursor()
+    cur.execute("""
+        INSERT INTO tenant_config (key, value) VALUES ('vehicle_compat_source', %s)
+        ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value
+    """, (source,))
+    conn.commit()
+    cur.close()
+    conn.close()
+    return jsonify({'message': 'Vehicle compatibility source updated', 'source': source})