Upgrade Drasi server to use Rust 195

[ruokun-niu]

Description

This pull request upgrades the Rust version of Drasi server to 1.95

Type of change

• This pull request fixes a bug in Drasi and has an approved issue (issue link required).
• This pull request adds or changes features of Drasi and has an approved issue (issue link required).
• This pull request is a minor refactor, code cleanup, test improvement, or other maintenance task and doesn't change the functionality of Drasi (issue link optional).

Fixes: #issue_number

[Copilot]

Pull request overview

This pull request upgrades the repository’s pinned Rust toolchain to 1.95.0 and aligns key CI workflows to use a corresponding reusable workflow ref, with a small Rust code cleanup to use is_multiple_of(2) for an evenness check.

Changes:

• Pin Rust toolchain from 1.88.0 to 1.95.0 via rust-toolchain.toml.
• Update CI workflows (test/lint/audit) to use drasi-project/.github reusable workflows at @rust195.
• Minor refactor in YAML comment parsing logic to use is_multiple_of(2) instead of % 2 == 0, plus add a Copilot security guidance document.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/api/models/solution.rs	Minor refactor: uses is_multiple_of(2) for quote-balance check.
rust-toolchain.toml	Pins repository Rust toolchain to 1.95.0.
.github/workflows/test.yml	Points unit test reusable workflow ref to @rust195.
.github/workflows/lint.yml	Points lint reusable workflow ref to @rust195.
.github/workflows/cargo-audit.yml	Points audit reusable workflow ref to @rust195.
.github/copilot-instructions.md	Adds OpenSSF-style security guidance for Copilot suggestions.

---

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