chore(deps): bump the go providers to current go main to deliver the library fixes #791

Problem

The platform pins the cloud-commitments-go modules at older commits, so several library fixes do not reach users. The pins on origin/main (go.mod, checked at 7e2a3d8 plus #778's merge 525e6ad):

• pkg a9a426224031
• providers/aws bcc0dfc49227 (moved there by fix(purchase): refuse retry and re-drive of AWS EC2 and Redshift purchases #778)
• providers/azure e24345ce68f8
• providers/gcp 2c18f303abfc

go main now also includes:

• go#297: EC2/Redshift purchases are sent once (no SDK resend)
• go#300: RDS offering lookup is an exact match and refuses Oracle and SQL Server
• go#305: zonal EC2 RIs keep their AZ. A stored zonal rec WITHOUT an AZ now errors with "re-fetch"
• go#306: recfilter drops RIs with unknown coverage
• go#318: pkg pins

Pending in go: go#314, go#317, go#307.

Behaviour changes the platform must be ready for

• A zonal rec with no AZ now errors (stored recs need a re-fetch).
• Oracle and SQL Server RDS purchases are refused.
• EC2 rejects an empty Platform, Tenancy or Scope before sending (already live since fix(purchase): refuse retry and re-drive of AWS EC2 and Redshift purchases #778).
• RunAutoExchange headroom and the RIExchangeStore interface (the platform already has these).

Plan

The bump needs its own plan and an Opus review, not a blind go get. Map each behaviour change to the platform callers it affects and to how a user sees it (for example, the error a user gets for an AZ-less zonal rec).

Blocked on: go#314 and go#317 merging; the AZ-scoped EC2 rec issue filed alongside this one (purchase guard, idempotency key and recommendations natural key ignore the AZ).

Related: go#289, go#295, go#288, go#190, go#308.