feat(drs-client): generic createSchedule with fixed cadences + tenant-isolation guards

[dzehnder]

Summary

Adds a generic DrsClient#createSchedule(...) to @adobe/spacecat-shared-drs-client for creating recurring DRS schedules on a fixed cadence — the mechanism the LLMO "prompt suggestion" pipelines (prompt_generation_semrush, prompt_generation_agentic_traffic, prompt_generation_synthetic_personas) need to run on a recurring basis and at onboarding. Sibling to the existing createExperimentSchedule; both now build the POST /schedules envelope through one shared private #buildScheduleBody, so the two paths cannot drift.

This is Phase 2 of the DRS prompt-suggestion schedules + onboarding-triggers effort. spacecat-api-service consumes createSchedule in a downstream PR (onboarding triggers); spacecat-audit-worker also depends on this client, and the change is purely additive so it is unaffected.

New API

createSchedule({
  siteId,                     // required
  providerIds,                // required, non-empty string[]
  cadence,                    // required, one of SCHEDULE_CADENCES
  description,                // optional (<= 1024 chars)
  enableBrandPresence = false,
  providerParameters,         // optional passthrough
  priority = 'HIGH',          // 'HIGH' | 'LOW'
  metadata,                   // optional
  triggerImmediately = false,
  timeout,
}) => Promise<{ scheduleId: string, alreadyExisted: boolean }>

New export: SCHEDULE_CADENCES = { TWICE_MONTHLY: 'twice_monthly', QUARTERLY: 'quarterly' }.

Design decisions

• Constrained cadence, not free-form cron. frequency is always 'cron'; the cron is derived from the cadence enum — a raw cron string is never accepted. twice_monthly -> 0 {H} 1,15 * * where H is a deterministic per-site hour (thundering-herd guard); quarterly -> 0 8 1 1,4,7,10 *. This closes the "leaked x-api-key sets * * * * *" fleet-wide Fargate-storm risk.
• Tenant-isolation hardening (defense in depth). A caller-supplied imsOrgId (also ims_org_id / imsorgid, any case, at any nesting depth) inside job_config is rejected. DRS derives the isolation key from site_id server-side; the client never accepts an org id. The guard is in the shared body-builder, so createExperimentSchedule gets it too.
• Size caps. description capped at 1024 chars and the serialized job_config at 100 KB (DynamoDB oversized-item guard).
• API key stays header-only and is never a logged argument.
• Idempotent. A 409 dedup from DRS is treated as success (alreadyExisted: true), matching createBrandPresenceSchedule.

Tests

npm run lint and npm test for the package both pass locally: 133 passing, 100% statements / branches / functions / lines (package enforces 100% branch coverage). New coverage includes cadence-derived cron, per-site jitter determinism, 409 dedup, imsOrgId rejection (nested + in arrays), size caps, and error paths.

Versioning

Additive feat: — semantic-release will publish 1.14.0 (current 1.13.0). No breaking change.

🤖 Generated with Claude Code

[github-actions]

This PR will trigger a minor release when merged.