feat(release): automate GitHub releases and tagging for Obsidian plugin

[cto-new]

Summary

Introduce automated release and tagging for the Obsidian plugin using GitHub Actions. Adds build, versioning, and release publishing workflows; updates docs and tooling to streamline version management and artifact publishing.

Details

• Added GitHub Actions workflows: build.yml (CI validation), version-bump.yml (version management), release.yml (artifact publishing and GitHub Release creation)
• Implemented automated release publishing: production build outputs (main.js, manifest.json, styles.css, versions.json); uploads artifacts to Release with checksums and release notes
• Updated version management: version-bump.mjs ensures manifest and versions.json stay in sync; package.json now includes prepare-release script
• Created release tooling: scripts/prepare-release.sh for pre-release validation
• Documentation and templates: RELEASE.md, README updates, WORKFLOWS README, QUICK_REFERENCE.md, PULL_REQUEST_TEMPLATE.md, ISSUE_TEMPLATE/release.md
• Minor improvements: fixed versions.json formatting, ensured Obsidian compatibility (no v prefix in tags; tag equals manifest version)
• Impact: improves repeatability, traceability, and automation for plugin releases with minimal manual steps; no breaking changes