fix(seed): route prisma db seed through pnpm run for cwd resolution

prisma db seed failed with "Cannot find module './seed.ts'" because
the spawned ts-node command inherited the user's cwd (apps/portal-bff/)
and resolved apps/portal-bff/prisma/seed.ts to
apps/portal-bff/apps/portal-bff/prisma/seed.ts (doubled).

pnpm run resets cwd to the package's root (workspace root) before
running the script. Routing prisma.seed through pnpm run db:seed
makes the path resolution cwd-invariant - works the same whether the
user invokes from the workspace root or from apps/portal-bff/.

Two-line diff: new db:seed script + prisma.seed delegates to it.
Side benefit: pnpm db:seed is directly callable.

package.json

@@ -16,7 +16,8 @@
     "grpc:sync": "node scripts/sync-ai-protos.mjs",
     "docs:dev": "vitepress dev docs",
     "docs:build": "vitepress build docs",
-    "docs:preview": "vitepress preview docs"
+    "docs:preview": "vitepress preview docs",
+    "db:seed": "ts-node --transpile-only --compiler-options {\"module\":\"CommonJS\",\"esModuleInterop\":true,\"target\":\"ES2020\"} apps/portal-bff/prisma/seed.ts"
   },
   "private": true,
   "lint-staged": {
@@ -58,7 +59,7 @@
   },
   "prisma": {
     "schema": "apps/portal-bff/prisma/schema.prisma",
-    "seed": "ts-node --transpile-only --compiler-options {\"module\":\"CommonJS\",\"esModuleInterop\":true,\"target\":\"ES2020\"} apps/portal-bff/prisma/seed.ts"
+    "seed": "pnpm run db:seed"
   },
   "devDependencies": {
     "@analogjs/vite-plugin-angular": "~2.5.0",