docs(release): standardize release and contributor writing

[qenterra]

Purpose

Standardizes commit messages, PR descriptions and review comments, changelogs, release notes, and publication updates so contributors use the same structure and terminology across QenTerra repositories.

Scope

Adds docs/RELEASE_WRITING.md as a shared release-writing guide and connects it to contributor and release documentation. Aligns PR templates and generated-release categories. Makes generated notes use canonical categories and complete version titles, accepts canonical and historical changelog date separators, and preserves reference-link precedence and code literals. Adds 21 focused tests and runs them in the release workflow.

Verification

• Repository governance passes locally with zero errors and warnings.

• Full base-to-staged whitespace verification includes new files.

• node --test scripts/release-notes.test.mjs: 21 tests passed.

• node scripts/verify-docs.mjs: 40 Markdown files passed.

• node scripts/verify-release.mjs v1.0.0 passed.

• Formatting, relative-link, history, and whitespace checks passed.

Evidence

Verified revision: 3eb2b1afa6d6fa0d903d88aa51cfaf8361aee139. Independent review checked the isolated publication diff and preservation of existing release history. Product runtime and manual acceptance checks were not rerun for this editorial change.

Risk and recovery

No product version, dependency, or data migration changes. Revert this commit to restore prior editorial behavior. Existing publishing mechanics retain their current behavior; this change does not certify all release automation.

Documentation and release

The Unreleased changelog records the adoption. No tag, release, binary upload, or deployment is part of this PR.

Checklist

• The title follows Conventional Commits.
• The diff contains one coherent outcome.
• Relevant checks and their limits are recorded.
• Contributor and release documentation are updated.