chore: adopt Biome + Stylelint, modernize CI/CD, add security/support docs, minor JS fixes

- Linting/format
  - Replace ESLint/Prettier with Biome; remove old configs; add `biome.json`; update scripts
  - Tailwind-friendly `.stylelintrc.yaml`; Stylelint and Biome pass
  - Enable Biome across `modules/**`; prune legacy JS globals; ignore oversized `devicon.json`

- Code fixes
  - `hb-theme.js`: avoid assignment-in-expressions; clearer dataset updates
  - `hugoblox-slides.js`: fix inner var scope (var → let); apply formatting

- CI/CD
  - Split lint/build workflows; add path filters; Node via Corepack (pnpm from package.json)
  - Hugo pinned to env `HUGO_VERSION`; add consistency check vs `starters/academic-cv/hugoblox.yaml`
  - Nightly starters matrix build (academic-cv, landing-page); CodeQL weekly; resource caches

- Workflows/Community
  - Greeter: switch to `pull_request_target`; add Contributor Guide to PR message
  - PR labeler for path-based labels

- Repo policies/docs
  - `CODEOWNERS` for `@gcushen`
  - `SECURITY.md`, `SUPPORT.md`
  - Documented branch protection in `.github/settings.yml`
  - Move `CODE_OF_CONDUCT.md` to `.github/`

- docs(zh): update `README.zh.md` translation

Notes:
- pnpm is sourced from `package.json: packageManager` via Corepack; no hard-coded pnpm versions in CI.

.github/SUPPORT.md

@@ -0,0 +1,20 @@
+# Support
+
+Need help? Here’s how to get support efficiently:
+
+- Discord: https://discord.gg/z8wNYzb
+- GitHub Discussions: https://github.com/HugoBlox/hugo-blox-builder/discussions
+- Docs & Guides: https://docs.hugoblox.com/
+- Issues: use for confirmed bugs or well-scoped feature requests only
+
+Tips for fast responses:
+
+- Share versions (Hugo, module, OS) and a minimal reproduction
+- Paste relevant logs/console output
+- State expected vs actual behavior
+- Attach screenshots to visually explain the issue
+
+Pro support & templates:
+
+- Pro templates: https://hugoblox.com/pro
+- Pro Discord Channel (request to be added): https://discord.gg/z8wNYzb