Update golang to 1.25 and also update linter

[kellyfj]

Motivation

• As a prelude to updating testcontainers (to fix a CVE in the underlying docker dependency) we need
  to upgrade Go to 1.25 and this requires a linter update too
• See Update TestContainers and change docker depenency to moby #1513 which depends on this

Modifications

• bump Go version from 1.24 to 1.25 in go.mod, Makefile, and CI matrices
• upgrade golangci-lint to v2.12.2 and fix Makefile install path to /v2 module
• migrate golangci config to v2 format and disable noisy govet inline analyzer
  • See https://golangci-lint.run/docs/product/migration-guide/ for more details
  • the v2 file was generated via golangci-lint migrate and then some tweaks based on failures.
• update GitHub Action to golangci-lint-action v9.2.1 (pinned SHA) and pin linter version
• fix lint findings across codebase (prealloc, revive naming/flow, ineffassign)
• verify lint passes: make lint reports 0 issues

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): No
• The public API: no
• The schema: no
• The default values of configurations: no
• The wire protocol: no

Documentation

• Does this pull request introduce a new feature? no