[DOCS] Add cloud store backend sync recipe (#11986)

[TemidayoA]

Closes #11986

• Description of PR changes above includes a link to an existing GitHub issue
• PR title is prefixed with one of: [BUGFIX], [FEATURE], [DOCS], [MAINTENANCE], [CONTRIB], [MINORBUMP]
• Code is linted - run invoke lint (uses ruff format + ruff check)
• Appropriate tests and docs have been updated
• For any behavioral change to a data source, validation mechanic, or Expectation, at least one integration test exists in tests/integration/data_sources_and_expectations (see AGENTS.md#integration-test-requirement)
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Summary

Adds a new docs recipe covering the supported sync-based workflow for storing GX artifacts (Expectations, Validation Results, Checkpoints, Data Docs) in cloud object storage, replacing the removed TupleGCSStoreBackend, TupleS3StoreBackend, and TupleAzureBlobStoreBackend store backends from GX 1.0.

Follows the configure_data_docs/ pattern as requested in the issue:

• cloud_store_backend_sync/cloud_store_backend_sync.md — main guide (pull → run → push workflow, config-as-read-only, safe results syncing, single-writer Data Docs)
• cloud_store_backend_sync/_backends/_gcs.md, _aws.md, _azure.md — per-provider partials
• cloud_store_backend_sync/_examples/cloud_store_backend_gcs.py, _aws.py, _azure.py — tested example scripts, wired via <snippet> tags
• Registered each example script as an IntegrationTestFixture in docs/docusaurus/docs/components/examples_under_test.py with the corresponding BackendDependencies flag (GCS / AWS / AZURE)

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[TemidayoA]

PR is up for #11986 — @joshua-stauffer, could you approve the workflow runs when you get a chance?

[TemidayoA]

Note on folder structure: the issue suggested placing this content under configure_metadata_stores/ or configure_data_docs/, but since the guide covers both the artifact-sync workflow and the Data Docs single-writer pattern together (as one end-to-end recipe), I put it in its own cloud_store_backend_sync/ folder instead of splitting across the two existing guides.

[joshua-stauffer]

Thanks @TemidayoA! I'll have a chance to review the content in detail later this week. I built the docs preview (see link above), I noticed that it's missing from the navbar and the section overview. Two places to add a link:

1. docs/docusaurus/sidebars.js (around line 131-137) — the configure_project_settings category has an explicit list of doc IDs; cloud_store_backend_sync isn't in it. It needs a new entry: { type: 'doc', id: 'core/configure_project_settings/cloud_store_backend_sync/cloud_store_backend_sync' }. This is the one that actually matters — without it, the page has no sidebar entry and (per Docusaurus's docs-only-sidebar behavior) no prev/next links either.
2. docs/docusaurus/docs/core/configure_project_settings/configure_project_settings.md — the section overview page renders a of entries (Metadata Stores, Data Docs, Credentials, Secrets Managers, Analytics Events). A new LinkCard pointing to="/core/configure_project_settings/cloud_store_backend_sync" should be added so the page is discoverable from the section landing page, not just deep-linkable.

The parallel data docs page should have the pattern you can follow.

[TemidayoA]

Thanks for the review, @joshua-stauffer I've added the sidebar entry and the LinkCard on the section overview page in commit f5d7bd4 , should be discoverable via both the navbar and the section landing page now.