Fix platform usage metering for thread and message events

[casey-brooks]

Platform usage remains empty in Console for thread/message activity.

Root cause from end-to-end tracing:

• Console queries MeteringGateway.QueryUsage with orgId, UNIT_COUNT, and labelFilters kind=thread/message.
• Metering stores/query labels and UTC timestamps correctly for supported kind filters.
• Threads service does invoke metering after CreateThread and SendMessage, but recordUsageAsync resolves org_id only from x-organization-id incoming metadata.
• Gateway forwards identity metadata only; Console sends organizationId in CreateThread request body, and SendMessage has no organizationId field.
• As a result, normal Console/Gateway thread and message creation skips metering emission before Metering receives any records.

Expected:

• Thread creation should record kind=thread usage with the created thread's organization_id.
• Message send should record kind=message usage with the message thread's organization_id.
• E2E should cover creating an org, creating a thread, sending a message, then verifying platform usage is non-zero via Console cards and/or MeteringGateway.QueryUsage.