Add categories and suppliers with CRUD routes

- category table with hierarchical parent_id, sort ordering, soft-delete
- supplier table with contact info, account number, payment terms
- CRUD routes for both with search on suppliers
- Zod validation schemas in @forte/shared
- Products will link to suppliers via join table (many-to-many)
- 26 tests passing

packages/backend/src/db/migrations/0004_peaceful_wendell_rand.sql

@@ -0,0 +1,30 @@
+CREATE TABLE "category" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"company_id" uuid NOT NULL,
+	"parent_id" uuid,
+	"name" varchar(255) NOT NULL,
+	"description" text,
+	"sort_order" integer DEFAULT 0 NOT NULL,
+	"is_active" boolean DEFAULT true NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"updated_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE "supplier" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"company_id" uuid NOT NULL,
+	"name" varchar(255) NOT NULL,
+	"contact_name" varchar(255),
+	"email" varchar(255),
+	"phone" varchar(50),
+	"website" varchar(255),
+	"account_number" varchar(100),
+	"payment_terms" varchar(100),
+	"notes" text,
+	"is_active" boolean DEFAULT true NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"updated_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+ALTER TABLE "category" ADD CONSTRAINT "category_company_id_company_id_fk" FOREIGN KEY ("company_id") REFERENCES "public"."company"("id") ON DELETE no action ON UPDATE no action;--> statement-breakpoint
+ALTER TABLE "supplier" ADD CONSTRAINT "supplier_company_id_company_id_fk" FOREIGN KEY ("company_id") REFERENCES "public"."company"("id") ON DELETE no action ON UPDATE no action;