make set.NewSet initializable

[keroxp]

No description provided.

[Copilot]

Pull request overview

This PR makes the generic set.NewSet constructor accept initial values while updating the Go toolchain and CI configuration.

Changes:

• Update NewSet[T] to accept a variadic list of initial values and populate the underlying sync.Map via Add.
• Add tests covering NewSet initialization behavior (empty, with values, duplicates, and different types) and refactor internal sync.Map.Range callbacks to use any.
• Bump the module’s Go version to 1.25 and update the GitHub Actions workflow to use newer action versions and Go 1.25.x.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
set/set.go	Extends NewSet to accept initial values and modernizes Range callback parameter types to any.
set/set_test.go	Adds comprehensive tests validating NewSet initialization semantics for ints and strings, including deduplication.
go.mod	Updates the declared Go version to 1.25 to align with the updated CI Go toolchain.
.github/workflows/push.yml	Refreshes CI configuration to use ubuntu-latest, newer checkout/setup-go actions, and Go 1.25.x.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.