feat(assets): add helpers package for chroma lexer map generation (#781)

- Add `packages/helpers` with CLI dispatcher pattern for code generation
- Add `chroma-lexers` helper that fetches lexer definitions from alecthomas/chroma
- Rename `$code-type-map` to `$chroma-lexers`, `_code-type.scss` to `_chroma-lexers.scss`
- Fix `fi-var` and `set-fi-var` to preserve quotes for string fallbacks
- Add `capitalize` utility to `packages/shared`
- Replace `console.*` with `consola` in packages
- Add `pnpm gen:lexers` script and CI workflow for auto-regeneration
- Update CLAUDE.md and CONTRIBUTING.md

.devcontainer/devcontainer.json

@@ -17,7 +17,8 @@
         "lruihao.hugo-partials-refs",
         "tamasfe.even-better-toml",
         "casualjim.gotemplate",
-        "SomewhatStationery.some-sass"
+        "SomewhatStationery.some-sass",
+        "gruntfuggly.todo-tree"
       ]
     }
   }