Add MCP server so Claude and ChatGPT can read and write drink data

Exposes the collection over the Model Context Protocol at /api/mcp, with 22
tools covering drinks, ratings, bar inventory, recipes, wishlist and taste
preferences, plus search/fetch aliases for ChatGPT's deep-research mode.

Authentication is a bearer token, the app's first header-borne credential -
every other route derives identity from the NextAuth cookie, which a machine
client cannot present. /api/mcp sits under the middleware's /api exclusion so
it can answer a JSON 401 with an RFC 9728 WWW-Authenticate challenge instead
of an HTML redirect to /login.

Tokens are stored as a SHA-256 hash rather than plaintext like Invite.token
and PasswordReset.token. Those are single-use and short-lived; this one is
long-lived and grants read/write over a whole collection, and the nightly
pg_dump keeps 14 days of history. Not encrypt(), which is reversible AES and
right only for outbound keys we must replay; not bcrypt, which cannot be
indexed and would turn verification into a table scan per request.

verifyMcpToken joins User.status on every call, mirroring the jwt callback, so
suspending a member kills their MCP access immediately rather than leaving the
token as a documented way to outlive suspension. It fails closed on a database
error, deliberately unlike the jwt callback, which keeps the session because a
throw there would sign out every user at once.

No tool reaches the Switchboard gateway. Claude and ChatGPT are language
models already, so they can reason over a bar inventory without the app paying
to do it a second time, and a remote client looping a vision call is not a
failure mode worth having. Account deletion, restore, gateway keys, admin
routes and shared-list creation are excluded too.

The OAuth models ship now but are unused; the token endpoint will write the
same McpAccessToken rows, so adding it later touches no verification code.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W1Ee4Mc1X1SX8HgYa52zu7

package.json

@@ -11,6 +11,7 @@
   "dependencies": {
     "@auth/prisma-adapter": "^2.11.1",
     "@aws-sdk/client-s3": "^3.1000.0",
+    "@modelcontextprotocol/server": "^2.0.0",
     "@prisma/client": "^6.19.2",
     "@tanstack/react-query": "^5.90.21",
     "@types/bcryptjs": "^2.4.6",
@@ -19,6 +20,7 @@
     "clsx": "^2.1.1",
     "html5-qrcode": "^2.3.8",
     "lucide-react": "^0.575.0",
+    "mcp-handler": "^2.1.0",
     "next": "14.2.35",
     "next-auth": "^5.0.0-beta.25",
     "openai": "^6.25.0",