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>

.github/workflows/files-changed.yml

@@ -57,7 +57,7 @@ jobs:
             backend:
               - "**/*.go"
               - "templates/**/*.tmpl"
-              - "assets/emoji.json"
+              - "public/assets/emoji.json"
               - "go.mod"
               - "go.sum"
               - "Makefile"
@@ -77,7 +77,7 @@ jobs:
               - "tools/**/*.json"
               - "tools/playwright.sh"
               - "tsconfig.json"
-              - "assets/emoji.json"
+              - "public/assets/emoji.json"
               - "package.json"
               - "pnpm-lock.yaml"
               - "pnpm-workspace.yaml"