FOCUS 1.4 phase 3: add ContractCommitment dataset

[flanakin]

Parent: #2120
Depends on: #2124 (phase 1) and #2127 (phase 2)

Goal

Add the FOCUS 1.3 Contract Commitment supplemental dataset across raw ingestion, transforms, hub functions, and the Latest aliases.

FOCUS 1.3 Contract Commitment columns (14 mandatory)

Column	Type	Description
BillingCurrency	string	ISO 4217
ContractCommitmentId	string	Unique commitment identifier
ContractCommitmentType	string	Provider-specific type
ContractCommitmentCategory	string	Spend or Usage
ContractCommitmentCost	real	Monetary value (nullable for Usage)
ContractCommitmentQuantity	real	Quantity (nullable for Spend)
ContractCommitmentUnit	string	Unit of measure
ContractCommitmentPeriodStart	datetime	Inclusive start
ContractCommitmentPeriodEnd	datetime	Exclusive end
ContractId	string	Parent contract identifier
ContractPeriodStart	datetime	Inclusive start
ContractPeriodEnd	datetime	Exclusive end
InvoiceIssuerName	string	Statement issuer
PricingCurrency	string	Pricing currency

Scope

`IngestionSetup_RawTables.kql`

• Add new table `ContractCommitment_raw` mirroring the column shape above (all string types in raw, parsed in transform).

`IngestionSetup_v1_3.kql`

• Add `ContractCommitment_transform_v1_3()` function: trivially passes through raw columns to typed final columns.
• Add `ContractCommitment_final_v1_3` table with the 14 columns above plus standard hub add-ons (`x_IngestionTime`, `x_SourceName`, `x_SourceProvider`, `x_SourceType`, `x_SourceVersion`).
• Add update policy `ContractCommitment_raw` -> `ContractCommitment_transform_v1_3` -> `ContractCommitment_final_v1_3`.

`HubSetup_v1_3.kql`

• Add `ContractCommitment_v1_3()` function reading `ContractCommitment_final_v1_3` directly. No older versions to union.

`HubSetup_Latest.kql`

• Add unversioned `ContractCommitment()` aliasing to `ContractCommitment_v1_3()`.

Branch

`flanakin/focus14-phase3-contractcommitment` off `flanakin/focus14-phase2-hubs-1.3` (depends on phase 2 for the v1_3 hub schema). PR target: `flanakin/focus14-phase2-hubs-1.3` until phase 2 merges, then will retarget.

Done when

• New raw, final, and hub tables / functions land.
• Pester tests still pass.
• Bicep compiles cleanly.