Expose DB workspace package entrypoint

[shaiananvari8]

/claim #743

Closes #3342

Summary

• add a Node-resolvable @freelanceflow/db package entrypoint that re-exports @prisma/client
• add matching package types and exports metadata for workspace consumers
• add a focused package import regression test proving the workspace package name resolves and exposes PrismaClient
• add a short demo GIF for the Algora bounty review

Root cause

packages/db was linked into node_modules by npm workspaces, but its package.json had no main, types, or exports entrypoint. Node package resolution therefore looked for a missing root index.js and require.resolve("@freelanceflow/db") failed.

Demo

Validation

• npm test -w packages/db
• node -e "const db = require('@freelanceflow/db'); console.log(typeof db.PrismaClient)"
• node -e "import('@freelanceflow/db').then((db) => { console.log(typeof (db.PrismaClient || db.default?.PrismaClient)); })"
• npm run build -w apps/web
• git diff --check