Port the new release infrastructure to 7.5-stable

[jamis]

In order to cut a new release of the 7.5 series, we need to port the release infrastructure to 7.5-stable.

[Copilot]

Pull Request Overview

This PR ports the new release infrastructure to the 7.5-stable branch by removing legacy release scripts and adding modern GitHub Actions-based release workflows, along with code quality tools.

• Removes old shell script-based release tooling (release.sh, build scripts, verification scripts)
• Adds GitHub Actions workflows for automated releases, CodeQL analysis, and RuboCop linting
• Updates Rakefile with new release infrastructure and development tools

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
spec/shared	Updates submodule commit reference
release/verify-signature.sh	Removes legacy gem signature verification script
release/mri/build.sh	Removes legacy MRI build script
release/mri/Dockerfile	Removes legacy Docker build configuration
release.sh	Removes legacy release shell script
product.yml	Adds product metadata configuration for new infrastructure
lib/mongoid/version.rb	Updates version format and adds documentation comments
gemfiles/standard.rb	Adds RuboCop gem dependencies for linting
gem-public_cert.pem	Removes public certificate file
Rakefile	Major refactor to support new release infrastructure and add development tasks
.rubocop.yml	Adds RuboCop configuration file
.github/workflows/rubocop.yml	Adds GitHub Actions workflow for RuboCop linting
.github/workflows/release.yml	Adds GitHub Actions workflow for automated gem releases
.github/workflows/codeql.yml	Adds GitHub Actions workflow for CodeQL security analysis

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[comandeo-mongo]

Test failures will be fixed in a follow-up PR