[Observability] Add relays counter

[bryanchriswhite]

Objective

Track the number of on-chain relays in addition to claims and compute units as they move through the claim/proof lifecycle (e.g. claimed, proven, expired, settled).

Origin Document

Goals

• Expose the number of relays in each lifecycle stage via observability.

Deliverables

• A PR that adds telemetry counter calls where appropriate; i.e. claim/proof upsert/settlement/expiration.
• A PR that updates relevant dashboards.

Non-goals / Non-deliverables

• Introducing additional metrics or labels
• Refactoring the telemetry pkg

General deliverables

• Comments: Add/update TODOs and comments alongside the source code so it is easier to follow.
• Testing: Add new tests (unit and/or E2E) to the test suite.
• Makefile: Add new targets to the Makefile to make the new functionality easier to use.
• Documentation: Update architectural or development READMEs; use mermaid diagrams where appropriate.

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Creator: @bryanchriswhite
Co-Owners: @red-0ne

[Olshansk]

@bryanchriswhite Did you not do this in another PR already or is this still a remaining open item?

[bryanchriswhite]

@bryanchriswhite Did you not do this in another PR already or is this still a remaining open item?

This is done in #644 which is still in review.