[erika-wallace]

Summary

This PR adds CRUD/operational coverage for Postgres maintenance to @heroku/sdk.

• Converts src/resources/data/maintenance.ts into src/resources/data/maintenance/ with one module per operation: info.ts, history.ts, run.ts, schedule.ts, window.ts (getWindow/updateWindow), and wait-for-completion.ts, tied together by a barrel index.ts that exports maintenanceExtensions.
• info keeps its prior behavior but changes signature from (appIdentity, addonIdentity?, options?) to (addonIdentity, options?), with app scoping now passed via options.appIdentity. It also now returns {addon, maintenance} instead of just the raw maintenance result.
• Adds history, run, schedule, getWindow, and updateWindow, each resolving the add-on once and supporting a beforeX hook (beforeHistory, beforeRun, beforeSchedule, beforeGetWindow, beforeUpdateWindow) that fires after resolution but before the underlying API call, plus AbortSignal support throughout.
• Adds waitForCompletion, which polls maintenance.info until status leaves running, with configurable intervalMs/timeoutMs, a beforeWait hook, and abort support.
• run and waitForCompletion reject Essential-tier databases up front (via isEssentialTier) without calling beforeRun/beforeWait or hitting the API; history, schedule, and the window operations intentionally don't apply this restriction.
• Fixes postgresDatabase.destroy() to catch heroku-fetch's NotFoundError instead of the synthetic AddonNotFoundError when probing for a cross-app match — the Platform API 404s on an unmatched add-on resolve rather than returning 200 with an empty array, so the prior check never actually caught the no-match case.
• Adds a ./resources/data/maintenance subpath export to package.json for the new directory layout.
• Updates examples/pg.ts to call maintenance.info with its new two-argument signature.

Type of Change

Breaking Changes (major semver update)

• Add a ! after your change type to denote a change that breaks current behavior

Feature Additions (minor semver update)

• feat: Introduces a new feature to the codebase

Patch Updates (patch semver update)

• fix: Bug fix
• deps: Dependency upgrade
• revert: Revert a previous commit
• chore: Change that does not affect production code
• refactor: Refactoring existing code without changing behavior
• test: Add/update/remove tests

Testing

Notes:

Steps:

1. Passing CI suffices

Screenshots (if applicable)

Related Issues

GUS work item: W-23385548

[tlowrimore-heroku]

LGTM!