feat: create inventory_items table migration

backend/migrations/00004_create_inventory_items_table.sql

@@ -0,0 +1,16 @@
+-- +goose Up
+CREATE TABLE inventory_items (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    name TEXT NOT NULL,
+    category TEXT NOT NULL,
+    type TEXT NOT NULL,
+    quantity DOUBLE PRECISION NOT NULL,
+    unit TEXT NOT NULL,
+    date_added TIMESTAMPTZ NOT NULL,
+    status TEXT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_inventory_items_category ON inventory_items(category);
+CREATE INDEX idx_inventory_items_status ON inventory_items(status);