docs: Add Data Explorer SKU availability guidance

[MSBrett]

Summary

Adds Data Explorer (Kusto) SKU regional availability information across FinOps Hubs documentation so users can self-serve when they hit SKU deployment failures.

Changes

File	What
errors.md	New error entry: "The sku {SkuName} is not supported in {region}" with PowerShell (Get-AzKustoSku) and REST API mitigation
deploy.md	Simple note that not all SKUs are available in every region, links to errors page
template.md	Cross-reference from dataExplorerSkuName parameter to errors page
deploy-finopshub.md	[!NOTE] linking to errors page for SKU issues
finops-hubs-deployment.md	Agent skill reference: availability commands and failure pattern

Context

Discovered during SRE Agent deployment to westus — Standard_E4d_v5 is not available there for Kusto clusters. The existing docs mention SKU selection but not how to verify regional availability or what to do when it fails.

The errors page (errors.md) is the canonical home for this — all other docs just link there. No alarmist callouts; just makes the information available where people need it.

[RolandKrummenacher]

Five files, clean canonical pattern (errors.md as home, others link there). Two factual issues to fix before merge, plus a couple of nice-to-haves — see inline comments.

[Copilot]

Pull request overview

Adds Azure Data Explorer (Kusto) SKU regional availability troubleshooting guidance to FinOps Hubs documentation, so users can self-serve when deployments fail due to unsupported SKUs in a given region.

Changes:

• Added a new “SKU not supported in region” troubleshooting entry with PowerShell (Get-AzKustoSku) and ARM REST API guidance.
• Added cross-references/notes in hub deployment and template docs pointing users to the canonical errors page.
• Updated the FinOps Hubs deployment agent-skill reference to include the SKU availability check pattern.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/templates/agent-skills/finops-toolkit/references/finops-hubs-deployment.md	Adds SKU availability check guidance and the common failure pattern to the deployment reference used by agents.
docs-mslearn/toolkit/powershell/hubs/deploy-finopshub.md	Adds a NOTE linking SKU failures to the canonical “common errors” entry; updates ms.date.
docs-mslearn/toolkit/hubs/template.md	Cross-references the SKU availability error from the dataExplorerSkuName parameter; updates ms.date.
docs-mslearn/toolkit/hubs/deploy.md	Adds a regional SKU availability reminder and link to the canonical error entry; updates ms.date.
docs-mslearn/toolkit/help/errors.md	Adds the canonical troubleshooting entry for “The sku {SkuName} is not supported in {region}”; updates ms.date.

[RolandKrummenacher]

Re-review ✅ — all items from the first round are resolved, verified against the source of truth (not just the "Fixed in…" replies):

• Default SKU — now correctly states Dev(No SLA)_Standard_D11_v2 is the default and E2a_v4 the lowest-cost option. Matches main.bicep (dataExplorerSku = 'Dev(No SLA)_Standard_D11_v2').
• api-version — bumped to 2025-02-14 in both errors.md and the agent-skill reference.
• Deep-links — template.md, deploy.md, and deploy-finopshub.md all link to #the-sku-skuname-is-not-supported-in-region; anchor slug is correct (braces stripped, inner text kept).
• {location}/{region} consistency — agent-skill reference now uses {region} throughout.

One trivial, non-blocking note: in errors.md the REST URL keeps {location} and the cmdlet example uses -Location — that's fine since those mirror the actual Azure API path segment and cmdlet parameter.

Docs-only, additive, follows the canonical "errors.md is home, everything links there" pattern. Good to merge.