Add missing endpoints and fix spec accuracy

- Add GET /teams endpoint with Team schema
- Add POST /templates (legacy, deprecated) with TemplateBuildRequest/TemplateLegacy schemas
- Add POST /templates/{templateID} (legacy rebuild, deprecated)
- Add POST /templates/{templateID}/builds/{buildID} (legacy start build, deprecated)
- Add Teams tag definition
- Fix TemplateBuildStatus enum values (waiting/error instead of pending/failed)
- Fix SandboxFilePath parameter required: false
- Add missing fields: NewSandbox (secure, allow_internet_access, network, mcp),
  Sandbox (trafficAccessToken), Template (createdBy, aliases, buildStatus),
  SandboxMetric (timestamp), ResumedSandbox (autoPause)
- Add missing parameters: signature, signature_expiration on /files endpoints,
  direction/level/source on build logs, level on build status
- Add missing error responses (400, 401, 403, 500) across endpoints

Author: beran-t