docs(release): Add 8.4.0 release notes

Document the 8.4.0 release in CHANGELOG.md so the release workflow can extract and publish the notes for the GitHub release object.

CHANGELOG.md

@@ -11,6 +11,46 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 *None pending.*
 
+## [8.4.0] - 2026-03-20 - "Discovery, Metadata, and Release Hardening"
+
+> Installable skill library update for Claude Code, Cursor, Codex CLI, Gemini CLI, Antigravity, and related AI coding assistants.
+
+Start here:
+
+- Install: `npx antigravity-awesome-skills`
+- Choose your tool: [README -> Choose Your Tool](https://github.com/sickn33/antigravity-awesome-skills#choose-your-tool)
+- Best skills by tool: [README -> Best Skills By Tool](https://github.com/sickn33/antigravity-awesome-skills#best-skills-by-tool)
+- Bundles: [docs/users/bundles.md](https://github.com/sickn33/antigravity-awesome-skills/blob/main/docs/users/bundles.md)
+- Workflows: [docs/users/workflows.md](https://github.com/sickn33/antigravity-awesome-skills/blob/main/docs/users/workflows.md)
+
+This release packages everything that landed after `v8.3.0`: new discovery and SEO surfaces for the catalog, GitHub Pages/web-app reliability fixes, metadata and index curation across the 1,273-skill registry, maintainer release/support polish, and the final merge sweep for PRs #363, #362, and #360.
+
+## New Skills
+
+- **None in this release** - `8.4.0` is a discovery, maintenance, and release-hardening cut rather than a new in-repo skill drop.
+
+## Improvements
+
+- **Catalog discovery and SEO**: Added repo growth discovery pages, finalized the web-app SEO layer for catalog routes, hardened JSON-LD/prerender behavior, expanded the home skills viewport, and improved GitHub Pages/base-path fetch fallbacks so the public catalog is more discoverable and stable.
+- **Registry curation**: Expanded curated and uncategorized category coverage, normalized legacy catalog categories, improved safe-skill categorization, and refreshed generated starter packs/bundles to better organize the 1,273-skill library.
+- **Metadata quality sweep**: Backfilled missing risk/source metadata, repaired actionable skill descriptions, and merged the `gha-security-review` metadata/usage cleanup so repository validation and review prompts stay more consistent.
+- **Infrastructure hardening**: Merged PR #363 to move CI intake to `tools/scripts/pr_preflight.cjs`, localize ESM handling for the Jetski Gemini loader docs, and keep the security/test pipeline green without breaking CommonJS entrypoints.
+- **Credits and repo polish**: Added `privacy-mask` to README credits, added the X/community reference update, refreshed the star-history/support surfaces, and kept release-facing onboarding/docs aligned with the current catalog state.
+
+## Who should care
+
+- **Claude Code users** get a more discoverable catalog, cleaner metadata, and improved release/maintenance hygiene around skill quality and source attribution.
+- **Cursor users** benefit from the same catalog-route SEO and GitHub Pages web-app fixes when browsing skills through the published site or mirrored install flows.
+- **Codex CLI users** benefit from the infrastructure hardening in PR #363 and the continued metadata cleanup that improves routing and maintenance behavior.
+- **Gemini CLI users** benefit from the Jetski Gemini loader hardening and the broader catalog/index curation that makes tool-specific discovery easier.
+
+## Credits
+
+- **[@Champbreed](https://github.com/Champbreed)** for the infrastructure hardening in PR #363 and the `gha-security-review` metadata/usage cleanup in PR #362
+- **[@fullstackcrew-alpha](https://github.com/fullstackcrew-alpha)** for the `privacy-mask` source attribution added in PR #360
+
+Upgrade now: `git pull origin main` to fetch the latest skills.
+
 ## [8.3.0] - 2026-03-19 - "Activation and Skill Expansion"
 
 > **Focused follow-up release for post-`v8.2.0` reliability, metadata, and marketplace improvements**