[User Story] Migrate pagerduty_schedule to pagerduty_schedulev2

[noahwhite]

Story Summary

As a platform engineer, I want pagerduty_schedule.ghost-stack_dev migrated to pagerduty_schedulev2, so that our PagerDuty schedule continues to function once the legacy v1 API resource is removed from the provider.

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✅ Acceptance Criteria

• opentofu/modules/pagerduty/main.tofu uses pagerduty_schedulev2 (not pagerduty_schedule) for ghost-stack_dev
• Existing schedule is migrated in state via tofu state mv or moved {} block — no schedule recreation (would lose history and disrupt on-call)
• tofu plan on develop shows no changes to the schedule after migration (in-place move only)
• Deprecation warning is gone from plan output
• On-call rotation continues uninterrupted after apply (verified in PagerDuty UI)

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📝 Additional Context

Current deprecation warning from tofu plan:

│ Warning: Deprecated Resource
│
│   with module.pagerduty.pagerduty_schedule.ghost-stack_dev,
│   on ../../modules/pagerduty/main.tofu line 259, in resource "pagerduty_schedule" "ghost-stack_dev":
│  259: resource "pagerduty_schedule" "ghost-stack_dev" {
│
│ Use pagerduty_schedulev2 instead. pagerduty_schedule uses the legacy v1 API
│ and will be removed in a future release.

• Resource location: opentofu/modules/pagerduty/main.tofu:259
• Provider version: pagerduty/pagerduty ~> 3.32.0 (check pagerduty_schedulev2 schema parity before migrating — attribute names may differ)
• Risk: Active on-call schedule; migration must use a moved block so OpenTofu renames the resource in state rather than destroying and recreating it
• Docs: https://registry.terraform.io/providers/PagerDuty/pagerduty/latest/docs/resources/schedulev2

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📦 Definition of Ready

• Acceptance criteria defined
• No unresolved external dependencies
• Story is estimated
• Team has necessary skills and access
• Priority is clear
• Business value understood

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✅ Definition of Done

• All acceptance criteria met
• Unit/integration tests written & passing
• Peer-reviewed
• Docs updated (if applicable)
• Verified in staging (if needed)
• No critical bugs/regressions

[linear]

GHO-132