enhance(emoji): update to Unicode 17, unify and lazy-load emoji data (#39363)

Generate emoji data from Unicode 17's `emoji-test.txt`, keeping existing
aliases. `public/assets/emoji.json` is now the single emoji data file,
also loaded by the backend. Rendered emoji drop their `aria-label`, the
dark theme inverts key on a new `data-alias` attribute instead.

Skin tone variants and their Gitea-only aliases are removed, GitHub has
none either.

Emoji autocompletion is now lazy-loaded with the markdown editor,
shrinking the index JS chunk from 653KB to 563KB.

---------

Signed-off-by: silverwind <me@silverwind.io>
Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: bircni <bircni@icloud.com>

modules/public/vitedev.go

@@ -183,7 +183,7 @@ func IsViteDevRequest(req *http.Request) bool {
 	//   - "{RepoRoot}/assets/*.json" just happens to live under the dir name "assets"; it is not related to frontend assets
 	//   - BAD DESIGN: indeed it is a "conflicted and polluted name" sample
 	switch path {
-	case "/assets/emoji.json", "/assets/codemirror-languages.json":
+	case "/assets/codemirror-languages.json":
 		return true
 	}
 	return false