Unify material supplier and balance controls

backend/routes/supplyRoutes.js

@@ -10,6 +10,7 @@ const {
     deleteReceipt,
     getSupplySummary,
     listFabricPlans,
+    listKnownSuppliers,
     saveMaterialDetails,
     listLots,
     listMovements,
@@ -27,6 +28,14 @@ router.get('/supply', verifyToken, async (req, res, next) => {
     }
 });
 
+router.get('/supply/suppliers', verifyToken, async (req, res, next) => {
+    try {
+        res.json(await listKnownSuppliers());
+    } catch (error) {
+        next(error);
+    }
+});
+
 router.get('/supply/receipts', verifyToken, async (req, res, next) => {
     try {
         res.json(await listReceipts());

backend/services/supplyService.js

@@ -158,6 +158,26 @@ const listMaterialDetails = async () => {
     return result.rows.map(mapMaterialDetails);
 };
 
+const listKnownSuppliers = async () => {
+    const result = await pool.query(`
+        SELECT DISTINCT supplier
+        FROM (
+            SELECT preferred_supplier AS supplier FROM supply_material_details
+            UNION ALL
+            SELECT supplier FROM supply_lots
+            UNION ALL
+            SELECT supplier FROM supply_receipts
+            UNION ALL
+            SELECT supplier FROM supply_fabric_plans
+            UNION ALL
+            SELECT supplier FROM production_yield_supplier_recommendations
+        ) sources
+        WHERE NULLIF(BTRIM(supplier), '') IS NOT NULL
+        ORDER BY supplier;
+    `);
+    return result.rows.map(row => row.supplier);
+};
+
 const saveMaterialDetails = async (materialKey, payload) => {
     const normalizedKey = normalizeKey(materialKey);
     if (!normalizedKey) throw createValidationError('Material inválido para edição.');
@@ -1062,6 +1082,7 @@ module.exports = {
     buildPurchaseNeeds,
     listFabricPlans,
     listMaterialDetails,
+    listKnownSuppliers,
     listLots,
     listMovements,
     listPurchaseNeeds,