Migra banco de dados de SQLite para PostgreSQL

- Muda provider Prisma de sqlite para postgresql
- Remove dependencias SQLite (better-sqlite3, adapter)
- Atualiza Better Auth para provider postgresql
- Simplifica prisma.ts removendo adapter SQLite
- Atualiza stack.yml para usar PostgreSQL existente com 2 replicas
- Remove logica de rebuild better-sqlite3 do start-web.sh
- Adiciona script de migracao de dados SQLite -> PostgreSQL
- Atualiza healthcheck para testar PostgreSQL via Prisma
- Habilita start-first deploy para zero-downtime

Melhoria: permite multiplas replicas e deploys sem downtime.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package.json

@@ -33,7 +33,6 @@
     "@hookform/resolvers": "5.2.2",
     "@noble/hashes": "2.0.1",
     "@paper-design/shaders-react": "0.0.68",
-    "@prisma/adapter-better-sqlite3": "^7.0.0",
     "@prisma/client": "^7.0.0",
     "@radix-ui/react-accordion": "^1.2.12",
     "@radix-ui/react-avatar": "^1.1.10",
@@ -62,7 +61,6 @@
     "@tiptap/starter-kit": "3.13.0",
     "@tiptap/suggestion": "3.13.0",
     "better-auth": "^1.3.26",
-    "better-sqlite3": "12.5.0",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "convex": "^1.29.2",