FOCUS 1.4 phase 1: extend Build-FocusConformance for multi-version + hubs report

[flanakin]

Parent: #2120

Goal

Make src/scripts/Build-FocusConformance.ps1 capable of generating conformance reports for multiple FOCUS versions and for the FinOps hubs output (not just Cost Management exports).

Background

Today the script defaults to -Branch v1.2 and produces a single conformance report against the Cost Management FOCUS export. Two gaps:

1. Multi-version: We now need 1.2, 1.3, and 1.4 reports concurrently for the docs.
2. Hubs vs Cost Management: The current report measures Microsoft's export against the FOCUS spec. There is no equivalent measuring the FinOps hubs enriched output (FOCUS columns + 184 x_ columns + ContractCommitment) against the spec — a gap surfaced during scoping (FOCUS 1.3 and 1.4 support across the toolkit #2120, step 3).

Scope

Multi-version support

• Accept -Versions array parameter (e.g., @('v1.2', 'v1.3', 'working_draft')).
• Generate one conformance report per version.
• Output filename pattern: conformance-full-report-1.3.md, conformance-summary-1.3.md. (Or keep single files if the doc structure stays version-pivoted.)

Hubs conformance report

• Add -Target parameter: CostManagement (default, current behavior) or Hubs.
• For Hubs target, the script reads from the hub schema (e.g., HubSetup_v1_2.kql column projections) instead of Cost Management export schemas, then measures against the FOCUS spec.
• Output: conformance-full-report-hubs-1.3.md etc.

Open questions to resolve in PR

• Where should the hubs schema be sourced? Parsing KQL is fragile; we may need a lightweight intermediate (e.g., a JSON manifest of columns per version) that both KQL generation and conformance reporting share. Propose your approach in the PR.
• Do we delete the old single-version report files, or version-suffix everything for clarity? Lean toward version-suffixing.

Branch

flanakin/focus14-phase1-conformance-tooling off flanakin/focus14. PR target: flanakin/focus14.

Done when

• Script can produce 1.2, 1.3, 1.4 reports for both targets.
• Generated reports for 1.2 (Cost Management target) match the existing report byte-for-byte (regression check).
• Pester unit test covering the new multi-version path.
• PR opened against flanakin/focus14.

[flanakin]

Closing as out of scope. Conformance reporting is generated only against official Microsoft Cost Management FOCUS releases, not as part of adding FOCUS 1.3 / 1.4 support to FinOps hubs. The existing single-version Build-FocusConformance.ps1 stays as-is until a real Cost Management release needs a new run.