chore: upgrade eslint plugins, remove eslint-plugin-github (#38046)

- Bump `eslint`, `typescript-eslint` and `eslint-plugin-unicorn` (to
v68), and configure the rules added in unicorn v66/v67/v68.
- Remove `eslint-plugin-github` and its workarounds (rules, type stub,
pnpm peer override, in-code `eslint-disable` comments); the rules worth
keeping are covered by `unicorn` equivalents.
- Apply the resulting fixes and autofixes across the JS codebase.

_Prepared with Claude (Opus 4.8)._

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/modules/codeeditor/main.ts

@@ -203,9 +203,7 @@ export async function createCodeEditor(textarea: HTMLTextAreaElement, filenameIn
         },
       }),
       cm.language.foldGutter({
-        markerDOM(open: boolean) {
-          return createElementFromHTML(svg(open ? 'octicon-chevron-down' : 'octicon-chevron-right', 13));
-        },
+        markerDOM: (open: boolean) => createElementFromHTML(svg(open ? 'octicon-chevron-down' : 'octicon-chevron-right', 13)),
       }),
       cm.view.highlightActiveLineGutter(),
       cm.view.highlightSpecialChars(),