Make metric/label name validation scheme explicit

[aknuds1]

Make the metric/label name validation scheme explicit throughout the code base, instead of directly or indirectly using the deprecated github.com/prometheus/common/model.NameValidationScheme global. I'm updating to a version of github.com/prometheus/common that deprecates functions using the aforementioned global as well as legacy equivalents:

• model.LabelName.IsValid
• model.LabelName.IsValidLegacy
• model.IsValidMetricName
• IsValidLegacyMetricName

Deprecating the above forces us to use explicit equivalents instead.

Does this PR introduce a user-facing change?

NONE

[Copilot]

Pull Request Overview

This PR makes metric and label name validation schemes explicit throughout the codebase instead of relying on the deprecated global github.com/prometheus/common/model.NameValidationScheme. The change replaces deprecated functions with explicit validation scheme parameters and updates the common library dependency.

Key changes:

• Replace deprecated validation functions with explicit model.UTF8Validation calls
• Add NameValidationScheme fields to configuration structs where needed
• Update function signatures to accept explicit validation schemes as parameters

Reviewed Changes

Copilot reviewed 38 out of 39 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
go.mod	Updates prometheus/common dependency version
Multiple config files	Add NameValidationScheme: model.UTF8Validation to relabel configurations in tests
Multiple source files	Replace deprecated validation calls with explicit scheme-based validation
rulefmt package	Update Parse/ParseFile functions to accept validation scheme parameter
relabel package	Add validation scheme field and update validation logic
main.go files	Pass validation schemes to managers and parsers

[ywwg]

This is good, and pretty clean! What worries me is the proliferation of validation and default-setting behavior that seems to be spread far and wide. I am wondering if there is a way to constrain that to specific places so that other people will not have to remember to do the right thing.

[ywwg]

I think the new util is helpful, thanks! For the yolostring discussion, resolve it however you like.