feat: add --escalation-policy-id flag to services update

[kwent]

Summary

• Adds --escalation-policy-id flag to rootly services update so CI/CD pipelines can attach or detach escalation policies on services without raw API calls (PRF-2820)
• Empty string (--escalation-policy-id="") sends JSON null to detach; non-empty string attaches
• Displays escalation policy ID in rootly services get detail view
• Parses escalation_policy_id from API responses across all service methods (List, Get, Create, Update)

Test plan

• go test ./internal/... — all 483 tests pass
• go vet ./... — no issues
• Manual: rootly services update <svc> --escalation-policy-id=<ep-id> then rootly services get <svc>
• Manual: rootly services update <svc> --escalation-policy-id="" to verify detach

[greptile-apps]

Greptile Summary

This PR adds --escalation-policy-id to rootly services update, enabling CI/CD pipelines to attach or detach escalation policies on services without raw API calls. The empty-string-to-null detach convention is cleanly handled at the UpdateService layer rather than leaking into the command layer.

• EscalationPolicyID is added to the Service struct and parsed consistently across all four service API methods (List, Get, Create, Update), so the field is always populated when the API returns it.
• The cmd.Flags().Changed() guard correctly prevents the field from being sent on unrelated updates, and the UpdateService function converts empty string to JSON null for the detach path.
• rootly services get conditionally displays the escalation policy ID in the detail view, consistent with how Color and OwnerTeamName are shown.

Confidence Score: 5/5

Safe to merge — the change is well-scoped, follows existing patterns throughout the codebase, and is covered by both API-level and command-level tests.

All four service API methods are updated consistently, the attach/detach logic is straightforward and tested with table-driven cases that assert on both the returned struct and the serialized request body, and no existing behavior is altered.

No files require special attention.

Important Files Changed

Filename	Overview
internal/api/client.go	Adds EscalationPolicyID to the Service struct and consistently parses it from all four service API methods (List, Get, Create, Update); the UpdateService function correctly converts empty string to JSON null for detach.
internal/cmd/services/update.go	Adds --escalation-policy-id flag using cmd.Flags().Changed() to avoid sending the field unless explicitly set; correctly maps kebab-case flag name to snake_case opts key.
internal/cmd/services/get.go	Adds EscalationPolicyID to the service detail view only when non-empty, consistent with how Color and OwnerTeamName are conditionally shown.
internal/api/client_mutations_test.go	Adds table-driven test covering both attach (non-empty ID) and detach (empty string → null) cases, with assertions on both the returned struct field and the serialized request body.
internal/cmd/services/cmd_test.go	Adds command-level tests for attach and detach flag scenarios; verifies error-free execution and non-empty output, consistent with existing cmd-test patterns.
internal/cmd/services/services_test.go	Updates TestServiceDetailRows fixture to include EscalationPolicyID and asserts it appears in the detail rows under the "Escalation Policy" label.

_{Reviews (1): Last reviewed commit: "✨ feat: [PRF-2820] add --escalation-poli..." | Re-trigger Greptile}