(BE-58,,59): extend db schema & build stock transfer api

- Extend DB schema for stock transfers
- Build stock transfer API (create,)

internal/database/migrations/20251014024355_create_stock_transfers.up.sql

@@ -0,0 +1,57 @@
+-- ===============================================================
+--  STOCK TRANSFERS (HEADER)
+-- ===============================================================
+
+CREATE SEQUENCE IF NOT EXISTS stock_transfer_seq START 1;
+
+CREATE TABLE IF NOT EXISTS stock_transfers (
+    id BIGSERIAL PRIMARY KEY,
+    movement_number VARCHAR(50) UNIQUE NOT NULL,
+    from_warehouse_id BIGINT NOT NULL,
+    to_warehouse_id BIGINT NOT NULL,
+    area_id BIGINT,
+    reason TEXT,
+    transfer_date DATE NOT NULL,
+    created_by BIGINT,
+    created_at TIMESTAMPTZ DEFAULT NOW(),
+    updated_at TIMESTAMPTZ DEFAULT NOW(),
+    deleted_at TIMESTAMPTZ
+);
+
+-- FOREIGN KEYS (dijalankan setelah semua tabel parent ada)
+DO $$
+BEGIN
+    IF EXISTS (SELECT 1 FROM pg_tables WHERE tablename = 'warehouses') THEN
+        ALTER TABLE stock_transfers
+            ADD CONSTRAINT fk_stock_transfers_from_warehouse
+            FOREIGN KEY (from_warehouse_id)
+            REFERENCES warehouses(id)
+            ON DELETE RESTRICT ON UPDATE CASCADE;
+        ALTER TABLE stock_transfers
+            ADD CONSTRAINT fk_stock_transfers_to_warehouse
+            FOREIGN KEY (to_warehouse_id)
+            REFERENCES warehouses(id)
+            ON DELETE RESTRICT ON UPDATE CASCADE;
+    END IF;
+
+    IF EXISTS (SELECT 1 FROM pg_tables WHERE tablename = 'areas') THEN
+        ALTER TABLE stock_transfers
+            ADD CONSTRAINT fk_stock_transfers_area
+            FOREIGN KEY (area_id)
+            REFERENCES areas(id)
+            ON DELETE SET NULL ON UPDATE CASCADE;
+    END IF;
+
+    IF EXISTS (SELECT 1 FROM pg_tables WHERE tablename = 'users') THEN
+        ALTER TABLE stock_transfers
+            ADD CONSTRAINT fk_stock_transfers_created_by
+            FOREIGN KEY (created_by)
+            REFERENCES users(id)
+            ON DELETE SET NULL ON UPDATE CASCADE;
+    END IF;
+END $$;
+
+-- INDEXES
+CREATE INDEX IF NOT EXISTS idx_stock_transfers_from_warehouse_id ON stock_transfers(from_warehouse_id);
+CREATE INDEX IF NOT EXISTS idx_stock_transfers_to_warehouse_id   ON stock_transfers(to_warehouse_id);
+CREATE INDEX IF NOT EXISTS idx_stock_transfers_transfer_date     ON stock_transfers(transfer_date);