feat: add AI Dental Shopping section with sidebar nav and Login Info page

- Add AI Dental Shopping to sidebar with Search/Tag and Login Info sub-pages
- Build full-stack Login Info CRUD: save vendor name, website, username, password per user
- Add ShoppingVendor Prisma model, run db push, regenerate client and Zod schemas
- Add storage layer, REST API at /api/shopping-vendors/, and frontend table with add/edit/delete modal

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/db/generated/prisma/package.json

@@ -1,5 +1,5 @@
 {
-  "name": "prisma-client-399048034458d5be2d4dc2eb570e77ca5c8345feb86d4b43b05fbd0cbc08be01",
+  "name": "prisma-client-763f714d62d731c0b365e1acdf19cac05ed4e6562d30b17cc8ffd11e6278eb14",
   "main": "index.js",
   "types": "index.d.ts",
   "browser": "default.js",