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>

prisma/migrations/migration_lock.toml

@@ -1,3 +1,3 @@
 # Please do not edit this file manually
 # It should be added in your version-control system (e.g., Git)
-provider = "sqlite"
+provider = "postgresql"