backend: org-scoped pharmacy inventory model

Add an `inventory` resource mirroring the prescriptions feature end-to-end:
Drizzle table (org-scoped, indexed), domain type, zod validation, service
(list/get/create/update/delete), and an RBAC-gated CRUD router mounted at
/api/inventory. Grant the new `inventory` statement to roles — pharmacy gets
read/write, full clinicians read/write/delete, reception/lab none — in both the
backend access control and (mirrored) the frontend. Record writes in the
activity log via a new `inventory` entity type. Includes the migration and an
idempotent demo seed script.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/drizzle/0012_wonderful_terrax.sql

@@ -0,0 +1,20 @@
+CREATE TABLE "inventory" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"organization_id" text NOT NULL,
+	"name" text NOT NULL,
+	"form" text DEFAULT '' NOT NULL,
+	"strength" text DEFAULT '' NOT NULL,
+	"unit" text DEFAULT '' NOT NULL,
+	"stock_quantity" integer DEFAULT 0 NOT NULL,
+	"reorder_threshold" integer DEFAULT 0 NOT NULL,
+	"location" text DEFAULT '' NOT NULL,
+	"expires_at" date,
+	"notes" text,
+	"created_by" text,
+	"created_at" timestamp DEFAULT now() NOT NULL,
+	"updated_at" timestamp DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+ALTER TABLE "inventory" ADD CONSTRAINT "inventory_organization_id_organization_id_fk" FOREIGN KEY ("organization_id") REFERENCES "public"."organization"("id") ON DELETE cascade ON UPDATE no action;--> statement-breakpoint
+ALTER TABLE "inventory" ADD CONSTRAINT "inventory_created_by_user_id_fk" FOREIGN KEY ("created_by") REFERENCES "public"."user"("id") ON DELETE set null ON UPDATE no action;--> statement-breakpoint
+CREATE INDEX "inventory_org_idx" ON "inventory" USING btree ("organization_id");

backend/drizzle/meta/_journal.json

@@ -85,6 +85,13 @@
       "when": 1781196252617,
       "tag": "0011_remap_viewer_to_member",
       "breakpoints": true
+    },
+    {
+      "idx": 12,
+      "version": "7",
+      "when": 1781279151289,
+      "tag": "0012_wonderful_terrax",
+      "breakpoints": true
     }
   ]
 }