Release v0.2.14 — Per-version release notes + /release-prep

Features

Browse the full changelog inside the app (#87) — a new Full changelog → button on the What's New modal opens a side-by-side history view: every published version on the left, the rendered notes on the right. Translations: en, pl, zh-CN.
/release-prep slash command + mermark-release-notes skill (#87) — invoke after gh pr create to bump the version, author a per-version release-notes file from the PR context, and regenerate CHANGELOG.md in one step.

Release notes now live in docs/release-notes/vX.Y.Z/RELEASE_NOTES.md (#87) — one folder per release. The app reads them straight from the bundle via Vite import.meta.glob('?raw') instead of fetching the GitHub Releases API at runtime. Root RELEASE_NOTES.md migrated to docs/release-notes/v0.2.12/; v0.2.13 backfilled with the actual Alt+Up/Down content (its GitHub release body had been a copy of v0.2.12).
scripts/gen-changelog.mjs (#87) — aggregates the folder into a root CHANGELOG.md in semver-desc order. Supports --check so CI can fail when the file is stale.
scripts/bump-version.mjs (#87) — single source of truth for a release bump: writes package.json, src-tauri/tauri.conf.json, src-tauri/Cargo.toml, creates the per-version stub, and runs gen-changelog. Resolves the current version from gh release list (fallback git describe --tags).
Shared release-notes stylesheet (#87) — the rendered-markdown CSS that lived inside WhatsNewModal.vue moved to src/styles/release-notes.css so both modals share one selector (.release-notes-content).