feat(ai): add Atlas Cloud provider

[binyangzhu000-sudo]

Summary

• add a first-class Atlas Cloud adapter to the existing ai-client provider registry
• reuse the OpenAI SDK for blocking and streaming chat completions through https://api.atlascloud.ai/v1
• register Atlas Cloud models and provider types across the AI client and shared microservice contracts
• support database configuration plus ATLASCLOUD_* / ATLAS_CLOUD_* environment aliases

Testing

• corepack pnpm --filter @team9/database test config.service.spec.ts --runInBand (1 passed)
• corepack pnpm --filter @team9/database build
• corepack pnpm --filter @team9/shared build
• corepack pnpm --filter @team9/ai-client build
• changed TypeScript files pass Prettier checks
• git diff --check
• Atlas Cloud /v1/models: HTTP 200, 121 models; confirmed all three registered model IDs

Notes

• The full database package test run completed 6/7 suites and 13/18 tests; only the existing seed.spec.ts suite failed because this local environment does not define POSTGRES_USER. The new Atlas Cloud config test passed in that run and independently.
• No README, documentation, logo, sponsor, credits, or partner changes. apps/server/.env.example only adds optional runtime configuration.