Restrict deployment Notion access to shared content

[mrubens]

Summary

• replace the hosted Notion MCP connection with a deployment-managed Notion internal integration
• keep the integration secret server-side and let Notion enforce access only to pages and data sources explicitly shared with the integration
• retain fail-closed read-only access by default, with an admin-controlled read-write option and per-tool overrides
• clear legacy broad OAuth credentials when an administrator configures the restricted integration
• update Settings guidance, runtime setup, tests, docs, and release notes

Validation

• pnpm lint
• pnpm check-types
• pnpm knip
• pnpm --filter @roomote/docs check
• focused types, API, SDK, web, worker, cloud-agent, and Slack tests
• full repository suite: 1 unrelated worker harness test timed out once; its complete 46-test file passed immediately on rerun

[roomote-community]

No new code issues found. See task

• Existing OAuth Notion configurations cannot be migrated in place from Settings (apps/web/src/components/settings/Integrations.tsx:1832).

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