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.

modules/blox-tailwind/assets/css/framework/base.css

@@ -5,7 +5,7 @@
     -moz-osx-font-smoothing: grayscale;
     text-rendering: optimizelegibility;
   }
-  
+
   body {
     line-height: 1.5;
   }
@@ -25,28 +25,28 @@
     text-decoration-color: rgb(var(--color-primary-300));
     font-weight: 500;
   }
-  
+
   .prose a:hover {
     color: rgb(var(--color-primary-600));
     text-decoration: none;
     border-radius: 0.09rem;
   }
-  
+
   .prose mark {
     color: rgb(var(--color-neutral-900));
     background-color: rgb(var(--color-primary-200));
     padding: 0.1rem 0.2rem;
     border-radius: 0.25rem;
   }
-  
+
   .dark .prose-invert a {
     text-decoration-color: rgb(var(--color-neutral-500));
   }
-  
+
   .dark .prose-invert a:hover {
     color: rgb(var(--color-primary-300));
   }
-  
+
   .dark .prose-invert mark {
     background-color: rgb(var(--color-primary-400));
     color: black;